disable button after removing data overlay

CHANGELOG

@@ -2,6 +2,8 @@ minerva (12.2.3) stable; urgency=medium
   * Bug fix: sorting of entries in "Edit project->overlays" dialog fixed (#790)
   * Bug fix: searching of chemicals stopped working due to expired SSL 
     certificate on https://ctdbase.org/
+  * Bug fix: remove button is disabled after starting removing of the data 
+    overlay (#791)
 
  -- Piotr Gawron <piotr.gawron@uni.lu>  Wed, 24 Apr 2019 17:00:00 +0200
 

frontend-js/src/main/js/gui/admin/EditProjectDialog.js

@@ -435,6 +435,7 @@ EditProjectDialog.prototype._createOverlayTable = function () {
 
   $(overlaysTable).on("click", "[name='removeOverlay']", function () {
     var button = this;
+    $(button).attr("disabled", true);
     return self.removeOverlay(parseInt($(button).attr("data"))).then(null, GuiConnector.alert);
   });