Merge pull request #500 from twistedsquare/selection-fix

Fixes issue #499: calling getCharacterBoundsOnScreen on a paragraph w…

Author: JordanMartinez

richtextfx/src/main/java/org/fxmisc/richtext/ParagraphText.java

@@ -156,7 +156,8 @@ public Bounds getRangeBoundsOnScreen(int from, int to) {
         PathElement[] rangeShape = getRangeShape(from, to);
 
         // switch out shapes to calculate the bounds on screen
-        List<PathElement> selShape = selectionShape.getElements();
+        // Must take a copy of the list contents, not just a reference:
+        List<PathElement> selShape = new ArrayList<>(selectionShape.getElements());
         selectionShape.getElements().setAll(rangeShape);
         Bounds localBounds = selectionShape.getBoundsInLocal();
         Bounds rangeBoundsOnScreen = selectionShape.localToScreen(localBounds);