Bug 81983 [preferences] Disabling and enabling folding on small file takes forever
3.1 M4 Using enable/disable folding on a small CU takes forever. This is caused by the recent change to apply the preference to all Java editors. In another (hidden) window (Debug) I had StyledText open which (understandably) took long to react on the preference change. Non-visible editor's should not react to this change until they become visible.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
*/
	protected void initializeViewerColors(ISourceViewer viewer) {
		
	}
	private boolean isJavaEditorHoverProperty(String property) {
		return	PreferenceConstants.EDITOR_TEXT_HOVER_MODIFIERS.equals(property);
	}
	
	/**
	 * Returns a segmentation of the line of the given viewer's input document appropriate for
	 * BIDI rendering. The default implementation returns only the string literals of a java code
	 * line as segments.
	 * 
	 * @param viewer the text viewer
	 * @param lineOffset the offset of the line
	 * @return the line's BIDI segmentation
	 * @throws BadLocationException in case lineOffset is not valid in document
	 */
	public static int[] getBidiLineSegments(ITextViewer viewer, int lineOffset) throws BadLocationException {
			
		IDocument document= viewer.getDocument();
		if (document == null)
			return null;
			
		IRegion line= document.getLineInformationOfOffset(lineOffset);
		ITypedRegion[] linePartitioning= TextUtilities.computePartitioning(document, IJavaPartitions.JAVA_PARTITIONING, lineOffset, line.getLength(), false);
		
		List segmentation= new ArrayList();
		for (int i= 0; i < linePartitioning.length; i++) {
			if (IJavaPartitions.JAVA_STRING.equals(linePartitioning[i].getType()))