#479 Fixed NPE when thread start calculating dialog size while dialog is hiding.

core/src/cz/nic/tablexia/util/ui/dialog/TablexiaComponentDialog.java

@@ -214,6 +214,7 @@ public class TablexiaComponentDialog extends Stack {
     }
 
     public void hide(boolean animated) {
+        componentsSizeComputed = true; //prevent recalculating the size of newly created dialog if going to hide it right after showing
         if (animated) {
             backgroundLayer.addAction(Actions.sequence(Actions.fadeOut(FADE_OUT_DURATION, FADE_OUT_INTERPOLATION)));
             addAction(Actions.sequence(Actions.fadeOut(FADE_OUT_DURATION, FADE_OUT_INTERPOLATION), Actions.run(new Runnable() {