Allow updating gpl based color schemes which are set to the

default random color scheme

Allows users to edit the color scheme inside QGIS and see the
effects immediately on next layer load

src/core/qgscolorscheme.cpp

@@ -16,6 +16,7 @@
  ***************************************************************************/
 
 #include "qgscolorscheme.h"
+#include "qgscolorschemeregistry.h"
 
 #include "qgsproject.h"
 #include "qgssymbollayerutils.h"
@@ -278,7 +279,19 @@ bool QgsGplColorScheme::setColors( const QgsNamedColorList &colors, const QStrin
   }
 
   QFile destFile( destFilePath );
-  return QgsSymbolLayerUtils::saveColorsToGpl( destFile, schemeName(), colors );
+  if ( QgsSymbolLayerUtils::saveColorsToGpl( destFile, schemeName(), colors ) )
+  {
+    if ( QgsApplication::colorSchemeRegistry()->randomStyleColorScheme() == this )
+    {
+      // force a re-generation of the random style color list, since the color list has changed
+      QgsApplication::colorSchemeRegistry()->setRandomStyleColorScheme( this );
+    }
+    return true;
+  }
+  else
+  {
+    return false;
+  }
 }
 
 
@@ -315,6 +328,12 @@ QgsUserColorScheme::QgsUserColorScheme( const QString &filename )
   {
     mName = mFilename;
   }
+
+  // we consider this scheme writable if the user has permission, OR
+  // if it DOESN'T already exist (since new schemes are only created when
+  // first written to)
+  QFileInfo sourceFileInfo( gplFilePath() );
+  mEditable = !sourceFileInfo.exists() || sourceFileInfo.isWritable();
 }
 
 QString QgsUserColorScheme::schemeName() const