Disable move on double-click

Sometimes it could happen that if one double click on a control the
slider "hangs" from then on as the control does not receive a "MousUp"
event and then the follow the mouse without actually holding it down.

This now additionally registers a MouseDoubleClick handler that disable
the move operation.

widgets/nebulaslider/org.eclipse.nebula.widgets.nebulaslider/src/org/eclipse/nebula/widgets/opal/nebulaslider/NebulaSlider.java

@@ -266,8 +266,14 @@ private void addMouseListeners() {
 				mouseDeltaX = xPosition - e.x;
 			}
 		});
+		addListener(SWT.MouseDoubleClick, e -> {
+			moving = false;
+		});
 
 		addListener(SWT.MouseUp, e -> {
+			if(!moving) {
+				return;
+			}
 			moving = false;
 			mouseDeltaX = 0;
 			if(movingValue != value) {