modal.js: Do not open multiple modal windows by clicking more than once

public/js/icinga/behavior/modal.js

@@ -42,6 +42,11 @@
         var $modal = _this.$ghost.clone();
         var $urlTarget = _this.icinga.loader.getLinkTargetFor($a, false);
 
+        _this.modalOpener = event.currentTarget;
+
+        // Disable pointer events to block further function calls
+        _this.modalOpener.style.pointerEvents = 'none';
+
         // Add showCompact, we don't want controls in a modal
         url = _this.icinga.utils.addUrlFlag(url, 'showCompact');
 
@@ -189,6 +194,10 @@
      * @param $modal {jQuery} The modal element
      */
     Modal.prototype.hide = function($modal) {
+        // Remove pointerEvent none style to make the button clickable again
+        this.modalOpener.style.pointerEvents = '';
+        this.modalOpener = null;
+
         $modal.removeClass('active');
         // Using `setTimeout` here to let the transition finish
         setTimeout(function () {