AbstractStoreSelectionModel has a flag mouseDown which tracks whether or not a mouse button is currently pressed. In TreeSelectionModel this flag is set within the onMouseDown method. Following is the current code

 protected void onMouseDown(MouseDownEvent mde) {
    XEvent e = mde.getNativeEvent().cast();

    mouseDown = true;
    boolean isSelected = isSelected(sel);
    boolean isMeta = e.getCtrlOrMetaKey();
    boolean isShift = e.getShiftKey();

    if (e.isRightClick() && isSelected) {
    } else {

    mouseDown = false;
As can be seen the flag is set to true but never set back to false in case the event is a right click. This causes errors, when for example events are triggered from a context menu.

Best regards,