Bug 53010 Editor preferences do not take effect on open editors
I-20040224 Go to the Java > Editor > Syntax preference page. Change the keyword color to red. Press Ok. At this point, we use to see the preview update. Not on this build (problem #1). Press Ok, and close the pref dialog. The java editor that was already open did not update. I had to close it and reopen it for the colors to take effect (problem #2)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
int offset= fActiveRegion.getOffset();
			int length= fActiveRegion.getLength();
			fActiveRegion= null;
				
			ISourceViewer viewer= getSourceViewer();
			if (viewer != null) {
				
				resetCursor(viewer);
				
				
				if (!redrawAll && viewer instanceof ITextViewerExtension2)
					((ITextViewerExtension2) viewer).invalidateTextPresentation(offset, length);
				else
					viewer.invalidateTextPresentation();
				
				
				if (viewer instanceof ITextViewerExtension3) {
					ITextViewerExtension3 extension= (ITextViewerExtension3) viewer;
					offset= extension.modelOffset2WidgetOffset(offset);
				} else {
					offset -= viewer.getVisibleRegion().getOffset();
				}
				try {
					StyledText text= viewer.getTextWidget();
					text.redrawRange(offset, length, false);
				} catch (IllegalArgumentException x) {
					JavaPlugin.log(x);
				}
			}
		}