Bug 43488 [typing] BadPositionCategoryException in LinkedPositionManager
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
Color foregroundColor= fColor;
			Color backgroundColor= oldStyleRange == null ? text.getBackground() : oldStyleRange.background;
			int fontStyle= oldStyleRange== null ? SWT.NORMAL : oldStyleRange.fontStyle;
			StyleRange styleRange= new StyleRange(offset, length, foregroundColor, backgroundColor, fontStyle);
			text.setStyleRange(styleRange);
			
			text.redrawRange(offset, length, true);
			fActiveRegion= region;
		}
		private void activateCursor(ISourceViewer viewer) {
			StyledText text= viewer.getTextWidget();
			if (text == null || text.isDisposed())
				return;
			Display display= text.getDisplay();
			if (fCursor == null)
				fCursor= new Cursor(display, SWT.CURSOR_HAND);
			text.setCursor(fCursor);
		}
		
		private void resetCursor(ISourceViewer viewer) {
			StyledText text= viewer.getTextWidget();
			if (text != null && !text.isDisposed())
				text.setCursor(null);
						
			if (fCursor != null) {
				fCursor.dispose();
				fCursor= null;
			}
		}
		/*