diff --git a/chrome/src/Makefile.in b/chrome/src/Makefile.in

--- a/chrome/src/Makefile.in

+++ b/chrome/src/Makefile.in

@@ -81,16 +81,17 @@ CPPSRCS		= \

 EXTRA_DSO_LDOPTS = \

                 $(MOZ_UNICHARUTIL_LIBS) \

                 $(MOZ_COMPONENT_LIBS) \

                 $(NULL)

 ifneq (,$(filter gtk2,$(MOZ_WIDGET_TOOLKIT)))

 EXTRA_DSO_LDOPTS += $(MOZ_GTK2_LIBS)

+LOCAL_INCLUDES += -I$(topsrcdir)/toolkit/xre

 endif

 ifneq (,$(filter mac cocoa,$(MOZ_WIDGET_TOOLKIT)))

 EXTRA_DSO_LDOPTS += $(TK_LIBS)

 endif

 include $(topsrcdir)/config/rules.mk

diff --git a/chrome/src/nsChromeRegistry.cpp b/chrome/src/nsChromeRegistry.cpp

--- a/chrome/src/nsChromeRegistry.cpp

+++ b/chrome/src/nsChromeRegistry.cpp

@@ -109,16 +109,17 @@

 #include "nsIStyleSheet.h"

 #include "nsISupportsArray.h"

 #include "nsIVersionComparator.h"

 #include "nsIWindowMediator.h"

 #include "nsIXPConnect.h"

 #include "nsIXULAppInfo.h"

 #include "nsIXULRuntime.h"

 #include "nsPresShellIterator.h"

+#include "nsKDEUtils.h"

 #define UILOCALE_CMD_LINE_ARG "UILocale"

 #define MATCH_OS_LOCALE_PREF "intl.locale.matchOS"

 #define SELECTED_LOCALE_PREF "general.useragent.locale"

 #define SELECTED_SKIN_PREF   "general.skins.selectedSkin"

 static NS_DEFINE_CID(kCSSLoaderCID, NS_CSS_LOADER_CID);

@@ -1607,16 +1608,17 @@ nsChromeRegistry::ProcessManifestBuffer(

   NS_NAMED_LITERAL_STRING(kPlatform, "platform");

   NS_NAMED_LITERAL_STRING(kXPCNativeWrappers, "xpcnativewrappers");

   NS_NAMED_LITERAL_STRING(kContentAccessible, "contentaccessible");

   NS_NAMED_LITERAL_STRING(kApplication, "application");

   NS_NAMED_LITERAL_STRING(kAppVersion, "appversion");

   NS_NAMED_LITERAL_STRING(kOs, "os");

   NS_NAMED_LITERAL_STRING(kOsVersion, "osversion");

+  NS_NAMED_LITERAL_STRING(kDesktop, "desktop");

   nsCOMPtr<nsIIOService> io (do_GetIOService());

   if (!io) return NS_ERROR_FAILURE;

   nsCOMPtr<nsIProtocolHandler> ph;

   rv = io->GetProtocolHandler("resource", getter_AddRefs(ph));

   NS_ENSURE_SUCCESS(rv, rv);

@@ -1650,35 +1652,39 @@ nsChromeRegistry::ProcessManifestBuffer(

       if (NS_SUCCEEDED(rv)) {

         CopyUTF8toUTF16(s, osTarget);

         ToLowerCase(osTarget);

       }

     }

   }

   nsAutoString osVersion;

+  nsAutoString desktop;

 #if defined(XP_WIN)

   OSVERSIONINFO info = { sizeof(OSVERSIONINFO) };

   if (GetVersionEx(&info)) {

     nsTextFormatter::ssprintf(osVersion, NS_LITERAL_STRING("%ld.%ld").get(),

                                          info.dwMajorVersion,

                                          info.dwMinorVersion);

   }

+  desktop = NS_LITERAL_STRING("win");

 #elif defined(XP_MACOSX)

   long majorVersion, minorVersion;

   if ((Gestalt(gestaltSystemVersionMajor, &majorVersion) == noErr) &&

       (Gestalt(gestaltSystemVersionMinor, &minorVersion) == noErr)) {

     nsTextFormatter::ssprintf(osVersion, NS_LITERAL_STRING("%ld.%ld").get(),

                                          majorVersion,

                                          minorVersion);

   }

+  desktop = NS_LITERAL_STRING("macosx");

 #elif defined(MOZ_WIDGET_GTK2)

   nsTextFormatter::ssprintf(osVersion, NS_LITERAL_STRING("%ld.%ld").get(),

                                        gtk_major_version,

                                        gtk_minor_version);

+  desktop = nsKDEUtils::kdeSession() ? NS_LITERAL_STRING("kde") : NS_LITERAL_STRING("gnome"); // TODO others?

 #endif

   char *token;

   char *newline = buf;

   PRUint32 line = 0;

   // outer loop tokenizes by newline

   while (nsnull != (token = nsCRT::strtok(newline, kNewlines, &newline))) {

@@ -1712,41 +1718,43 @@ nsChromeRegistry::ProcessManifestBuffer(

       PRBool platform = PR_FALSE;

       PRBool xpcNativeWrappers = PR_TRUE;

       PRBool contentAccessible = PR_FALSE;

       TriState stAppVersion = eUnspecified;

       TriState stApp = eUnspecified;

       TriState stOsVersion = eUnspecified;

       TriState stOs = eUnspecified;

+      TriState stDesktop = eUnspecified;

       PRBool badFlag = PR_FALSE;

       while (nsnull != (token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&

              !badFlag) {

         NS_ConvertASCIItoUTF16 wtoken(token);

         ToLowerCase(wtoken);

         if (CheckFlag(kPlatform, wtoken, platform) ||

             CheckFlag(kXPCNativeWrappers, wtoken, xpcNativeWrappers) ||

             CheckFlag(kContentAccessible, wtoken, contentAccessible) ||

             CheckStringFlag(kApplication, wtoken, appID, stApp) ||

             CheckStringFlag(kOs, wtoken, osTarget, stOs) ||

+            CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||

             CheckVersionFlag(kOsVersion, wtoken, osVersion, vc, stOsVersion) ||

             CheckVersionFlag(kAppVersion, wtoken, appVersion, vc, stAppVersion))

           continue;

         LogMessageWithContext(manifestURI, line, nsIScriptError::warningFlag,

                               "Warning: Unrecognized chrome registration modifier '%s'.",

                               token);

         badFlag = PR_TRUE;

       }

       if (badFlag || stApp == eBad || stAppVersion == eBad || 

-          stOs == eBad || stOsVersion == eBad)

+          stOs == eBad || stOsVersion == eBad || stDesktop == eBad)

         continue;

       nsCOMPtr<nsIURI> resolved;

       rv = io->NewURI(nsDependentCString(uri), nsnull, manifestURI,

                       getter_AddRefs(resolved));

       if (NS_FAILED(rv))

         continue;

@@ -1797,38 +1805,40 @@ nsChromeRegistry::ProcessManifestBuffer(

       }

       EnsureLowerCase(package);

       TriState stAppVersion = eUnspecified;

       TriState stApp = eUnspecified;

       TriState stOs = eUnspecified;

       TriState stOsVersion = eUnspecified;

+      TriState stDesktop = eUnspecified;

       PRBool badFlag = PR_FALSE;

       while (nsnull != (token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&

              !badFlag) {

         NS_ConvertASCIItoUTF16 wtoken(token);

         ToLowerCase(wtoken);

         if (CheckStringFlag(kApplication, wtoken, appID, stApp) ||

             CheckStringFlag(kOs, wtoken, osTarget, stOs) ||

+            CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||

             CheckVersionFlag(kOsVersion, wtoken, osVersion, vc, stOsVersion) ||

             CheckVersionFlag(kAppVersion, wtoken, appVersion, vc, stAppVersion))

           continue;

         LogMessageWithContext(manifestURI, line, nsIScriptError::warningFlag,

                               "Warning: Unrecognized chrome registration modifier '%s'.",

                               token);

         badFlag = PR_TRUE;

       }

       if (badFlag || stApp == eBad || stAppVersion == eBad ||

-          stOs == eBad || stOsVersion == eBad)

+          stOs == eBad || stOsVersion == eBad || stDesktop == eBad)

         continue;

       nsCOMPtr<nsIURI> resolved;

       rv = io->NewURI(nsDependentCString(uri), nsnull, manifestURI,

                       getter_AddRefs(resolved));

       if (NS_FAILED(rv))

         continue;

@@ -1859,38 +1869,40 @@ nsChromeRegistry::ProcessManifestBuffer(

       }

       EnsureLowerCase(package);

       TriState stAppVersion = eUnspecified;

       TriState stApp = eUnspecified;

       TriState stOs = eUnspecified;

       TriState stOsVersion = eUnspecified;

+      TriState stDesktop = eUnspecified;

       PRBool badFlag = PR_FALSE;

       while (nsnull != (token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&

              !badFlag) {

         NS_ConvertASCIItoUTF16 wtoken(token);

         ToLowerCase(wtoken);

         if (CheckStringFlag(kApplication, wtoken, appID, stApp) ||

             CheckStringFlag(kOs, wtoken, osTarget, stOs) ||

+            CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||

             CheckVersionFlag(kOsVersion, wtoken, osVersion, vc, stOsVersion) ||

             CheckVersionFlag(kAppVersion, wtoken, appVersion, vc, stAppVersion))

           continue;

         LogMessageWithContext(manifestURI, line, nsIScriptError::warningFlag,

                               "Warning: Unrecognized chrome registration modifier '%s'.",

                               token);

         badFlag = PR_TRUE;

       }

       if (badFlag || stApp == eBad || stAppVersion == eBad ||

-          stOs == eBad || stOsVersion == eBad)

+          stOs == eBad || stOsVersion == eBad || stDesktop == eBad)

         continue;

       nsCOMPtr<nsIURI> resolved;

       rv = io->NewURI(nsDependentCString(uri), nsnull, manifestURI,

                       getter_AddRefs(resolved));

       if (NS_FAILED(rv))

         continue;

@@ -1923,38 +1935,40 @@ nsChromeRegistry::ProcessManifestBuffer(

                               "Warning: malformed chrome overlay instruction.");

         continue;

       }

       TriState stAppVersion = eUnspecified;

       TriState stApp = eUnspecified;

       TriState stOs = eUnspecified;

       TriState stOsVersion = eUnspecified;

+      TriState stDesktop = eUnspecified;

       PRBool badFlag = PR_FALSE;

       while (nsnull != (token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&

              !badFlag) {

         NS_ConvertASCIItoUTF16 wtoken(token);

         ToLowerCase(wtoken);

         if (CheckStringFlag(kApplication, wtoken, appID, stApp) ||

             CheckStringFlag(kOs, wtoken, osTarget, stOs) ||

+            CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||

             CheckVersionFlag(kOsVersion, wtoken, osVersion, vc, stOsVersion) ||

             CheckVersionFlag(kAppVersion, wtoken, appVersion, vc, stAppVersion))

           continue;

         LogMessageWithContext(manifestURI, line, nsIScriptError::warningFlag,

                               "Warning: Unrecognized chrome registration modifier '%s'.",

                               token);

         badFlag = PR_TRUE;

       }

       if (badFlag || stApp == eBad || stAppVersion == eBad ||

-          stOs == eBad || stOsVersion == eBad)

+          stOs == eBad || stOsVersion == eBad || stDesktop == eBad)

         continue;

       nsCOMPtr<nsIURI> baseuri, overlayuri;

       rv  = io->NewURI(nsDependentCString(base), nsnull, nsnull,

                        getter_AddRefs(baseuri));

       rv |= io->NewURI(nsDependentCString(overlay), nsnull, nsnull,

                        getter_AddRefs(overlayuri));

       if (NS_FAILED(rv)) {

@@ -1979,38 +1993,40 @@ nsChromeRegistry::ProcessManifestBuffer(

                               "Warning: malformed chrome style instruction.");

         continue;

       }

       TriState stAppVersion = eUnspecified;

       TriState stApp = eUnspecified;

       TriState stOs = eUnspecified;

       TriState stOsVersion = eUnspecified;

+      TriState stDesktop = eUnspecified;

       PRBool badFlag = PR_FALSE;

       while (nsnull != (token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&

              !badFlag) {

         NS_ConvertASCIItoUTF16 wtoken(token);

         ToLowerCase(wtoken);

         if (CheckStringFlag(kApplication, wtoken, appID, stApp) ||

             CheckStringFlag(kOs, wtoken, osTarget, stOs) ||

+            CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||

             CheckVersionFlag(kOsVersion, wtoken, osVersion, vc, stOsVersion) ||

             CheckVersionFlag(kAppVersion, wtoken, appVersion, vc, stAppVersion))

           continue;

         LogMessageWithContext(manifestURI, line, nsIScriptError::warningFlag,

                               "Warning: Unrecognized chrome registration modifier '%s'.",

                               token);

         badFlag = PR_TRUE;

       }

       if (badFlag || stApp == eBad || stAppVersion == eBad ||

-          stOs == eBad || stOsVersion == eBad)

+          stOs == eBad || stOsVersion == eBad || stDesktop == eBad)

         continue;

       nsCOMPtr<nsIURI> baseuri, overlayuri;

       rv  = io->NewURI(nsDependentCString(base), nsnull, nsnull,

                       getter_AddRefs(baseuri));

       rv |= io->NewURI(nsDependentCString(overlay), nsnull, nsnull,

                        getter_AddRefs(overlayuri));

       if (NS_FAILED(rv))

@@ -2039,38 +2055,40 @@ nsChromeRegistry::ProcessManifestBuffer(

                               "Warning: malformed chrome override instruction.");

         continue;

       }

       TriState stAppVersion = eUnspecified;

       TriState stApp = eUnspecified;

       TriState stOs = eUnspecified;

       TriState stOsVersion = eUnspecified;

+      TriState stDesktop = eUnspecified;

       PRBool badFlag = PR_FALSE;

       while (nsnull != (token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&

              !badFlag) {

         NS_ConvertASCIItoUTF16 wtoken(token);

         ToLowerCase(wtoken);

         if (CheckStringFlag(kApplication, wtoken, appID, stApp) ||

             CheckStringFlag(kOs, wtoken, osTarget, stOs) ||

+            CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||

             CheckVersionFlag(kOsVersion, wtoken, osVersion, vc, stOsVersion) ||

             CheckVersionFlag(kAppVersion, wtoken, appVersion, vc, stAppVersion))

           continue;

         LogMessageWithContext(manifestURI, line, nsIScriptError::warningFlag,

                               "Warning: Unrecognized chrome registration modifier '%s'.",

                               token);

         badFlag = PR_TRUE;

       }

       if (badFlag || stApp == eBad || stAppVersion == eBad ||

-          stOs == eBad || stOsVersion == eBad)

+          stOs == eBad || stOsVersion == eBad || stDesktop == eBad)

         continue;

       nsCOMPtr<nsIURI> chromeuri, resolveduri;

       rv  = io->NewURI(nsDependentCString(chrome), nsnull, nsnull,

                       getter_AddRefs(chromeuri));

       rv |= io->NewURI(nsDependentCString(resolved), nsnull, manifestURI,

                        getter_AddRefs(resolveduri));

       if (NS_FAILED(rv))

@@ -2101,38 +2119,40 @@ nsChromeRegistry::ProcessManifestBuffer(

       }

       EnsureLowerCase(package);

       TriState stAppVersion = eUnspecified;

       TriState stApp = eUnspecified;

       TriState stOsVersion = eUnspecified;

       TriState stOs = eUnspecified;

+      TriState stDesktop = eUnspecified;

       PRBool badFlag = PR_FALSE;

       while (nsnull != (token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&

              !badFlag) {

         NS_ConvertASCIItoUTF16 wtoken(token);

         ToLowerCase(wtoken);

         if (CheckStringFlag(kApplication, wtoken, appID, stApp) ||

             CheckStringFlag(kOs, wtoken, osTarget, stOs) ||

+            CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||

             CheckVersionFlag(kOsVersion, wtoken, osVersion, vc, stOsVersion) ||

             CheckVersionFlag(kAppVersion, wtoken, appVersion, vc, stAppVersion))

           continue;

         LogMessageWithContext(manifestURI, line, nsIScriptError::warningFlag,

                               "Warning: Unrecognized chrome registration modifier '%s'.",

                               token);

         badFlag = PR_TRUE;

       }

       if (badFlag || stApp == eBad || stAppVersion == eBad || 

-          stOs == eBad || stOsVersion == eBad)

+          stOs == eBad || stOsVersion == eBad || stDesktop == eBad)

         continue;

       nsDependentCString host(package);

       PRBool exists;

       rv = rph->HasSubstitution(host, &exists);

       NS_ENSURE_SUCCESS(rv, rv);

       if (exists) {

diff --git a/modules/libpref/src/Makefile.in b/modules/libpref/src/Makefile.in

--- a/modules/libpref/src/Makefile.in

+++ b/modules/libpref/src/Makefile.in

@@ -97,8 +97,10 @@ GARBAGE		+= $(addprefix $(DIST)/bin/defa

 # Optimizer bug with GCC 3.2.2 on OS/2

 ifeq ($(OS_ARCH), OS2)

 nsPrefService.$(OBJ_SUFFIX): nsPrefService.cpp

 	$(REPORT_BUILD)

 	@$(MAKE_DEPS_AUTO_CXX)

 	$(ELOG) $(CCC) $(OUTOPTION)$@ -c $(COMPILE_CXXFLAGS:-O2=-O1) $(_VPATH_SRCS)

 endif

+

+LOCAL_INCLUDES += -I$(topsrcdir)/toolkit/xre

diff --git a/modules/libpref/src/nsPrefService.cpp b/modules/libpref/src/nsPrefService.cpp

--- a/modules/libpref/src/nsPrefService.cpp

+++ b/modules/libpref/src/nsPrefService.cpp

@@ -47,16 +47,17 @@

 #include "nsILocalFile.h"

 #include "nsIObserverService.h"

 #include "nsPrefBranch.h"

 #include "nsXPIDLString.h"

 #include "nsCRT.h"

 #include "nsCOMArray.h"

 #include "nsXPCOMCID.h"

 #include "nsAutoPtr.h"

+#include "nsKDEUtils.h"

 #include "nsQuickSort.h"

 #include "prmem.h"

 #include "pldhash.h"

 #include "prefapi.h"

 #include "prefread.h"

 #include "prefapi_private_data.h"

@@ -610,17 +611,18 @@ pref_LoadPrefsInDir(nsIFile* aDir, char 

         rv = rv2;

       }

     }

   }

   return rv;

 }

-static nsresult pref_LoadPrefsInDirList(const char *listId)

+static nsresult pref_LoadPrefsInDirList(const char *listId,

+    char const *const *aSpecialFiles = NULL, PRUint32 aSpecialFilesCount = 0)

 {

   nsresult rv;

   nsCOMPtr<nsIProperties> dirSvc(do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv));

   if (NS_FAILED(rv)) return rv;

   nsCOMPtr<nsISimpleEnumerator> dirList;

   dirSvc->Get(listId,

               NS_GET_IID(nsISimpleEnumerator),

@@ -629,17 +631,17 @@ static nsresult pref_LoadPrefsInDirList(

     PRBool hasMore;

     while (NS_SUCCEEDED(dirList->HasMoreElements(&hasMore)) && hasMore) {

       nsCOMPtr<nsISupports> elem;

       dirList->GetNext(getter_AddRefs(elem));

       if (elem) {

         nsCOMPtr<nsIFile> dir = do_QueryInterface(elem);

         if (dir) {

           // Do we care if a file provided by this process fails to load?

-          pref_LoadPrefsInDir(dir, nsnull, 0); 

+          pref_LoadPrefsInDir(dir, aSpecialFiles, aSpecialFilesCount); 

         }

       }

     }

   }

   return NS_OK;

 }

 //----------------------------------------------------------------------------------------

@@ -680,29 +682,41 @@ static nsresult pref_InitInitialObjects(

 #if defined(VMS)

       , "openvms.js"

 #elif defined(_AIX)

       , "aix.js"

 #endif

 #if defined(MOZ_WIDGET_PHOTON)

 	  , "photon.js"

 #endif		 

+      , "" // placeholder for KDE  (empty is otherwise harmless)

 #elif defined(XP_OS2)

       "os2pref.js"

 #elif defined(XP_BEOS)

       "beos.js"

 #endif

   };

+  if( nsKDEUtils::kdeSession()) { // TODO what if some setup actually requires the helper?

+      for( int i = 0;

+           i < NS_ARRAY_LENGTH(specialFiles);

+           ++i ) {

+          if( *specialFiles[ i ] == '\0' ) {

+              specialFiles[ i ] = "kde.js";

+              break;

+          }

+      }

+  }

+      

   rv = pref_LoadPrefsInDir(defaultPrefDir, specialFiles, NS_ARRAY_LENGTH(specialFiles));

   if (NS_FAILED(rv)) {

     NS_WARNING("Error parsing application default preferences.");

   }

-  rv = pref_LoadPrefsInDirList(NS_APP_PREFS_DEFAULTS_DIR_LIST);

+  rv = pref_LoadPrefsInDirList(NS_APP_PREFS_DEFAULTS_DIR_LIST, specialFiles, NS_ARRAY_LENGTH(specialFiles));

   NS_ENSURE_SUCCESS(rv, rv);

   NS_CreateServicesFromCategory(NS_PREFSERVICE_APPDEFAULTS_TOPIC_ID,

                                 nsnull, NS_PREFSERVICE_APPDEFAULTS_TOPIC_ID);

   nsCOMPtr<nsIObserverService> observerService = 

     do_GetService("@mozilla.org/observer-service;1", &rv);

diff --git a/toolkit/components/downloads/src/Makefile.in b/toolkit/components/downloads/src/Makefile.in

--- a/toolkit/components/downloads/src/Makefile.in

+++ b/toolkit/components/downloads/src/Makefile.in

@@ -92,8 +92,9 @@ EXTRA_COMPONENTS = \

   nsDownloadManagerUI.js \

   $(NULL)

 endif

 include $(topsrcdir)/config/rules.mk

 EXTRA_DSO_LDOPTS += $(MOZ_COMPONENT_LIBS)

+LOCAL_INCLUDES += -I$(topsrcdir)/toolkit/xre

diff --git a/toolkit/components/downloads/src/nsDownloadManager.cpp b/toolkit/components/downloads/src/nsDownloadManager.cpp