Fix some filemanager drag'n'drop with multiselect cases

src/components/filetree.html

@@ -62,7 +62,7 @@
       <tr ng-show="!(busy && !busyRefresh) && entries.length === 0">
         <td colspan="" class="text-center">{{ 'filemanager.list.empty' | tr }}</td>
       </tr>
-      <tr style="cursor: default" ng-hide="busy && !busyRefresh" entry-hashkey="{{ entry['$$hashKey'] }}" ng-repeat="entry in entries" ng-mousedown="onMousedown($event, entry)" draggable="true" ng-dragstart="dragStart($event, entry)" ng-drop="drop($event, entry)" context-menu="menuOptions" model="entry" ng-dragleave="dragExit($event, entry)" ng-dragover="dragEnter($event, entry)" ng-class="{ 'entry-hovered': entry.hovered, 'entry-selected': isSelected(entry) }">
+      <tr style="cursor: default" ng-hide="busy && !busyRefresh" entry-hashkey="{{ entry['$$hashKey'] }}" ng-repeat="entry in entries" ng-mouseup="onMouseup($event, entry)" draggable="true" ng-dragstart="dragStart($event, entry)" ng-drop="drop($event, entry)" context-menu="menuOptions" model="entry" ng-dragleave="dragExit($event, entry)" ng-dragover="dragEnter($event, entry)" ng-class="{ 'entry-hovered': entry.hovered, 'entry-selected': isSelected(entry) }">
         <td style="width: 42px; height: 42px" ng-dblclick="open(entry)" class="text-center">
           <i ng-show="!entry.previewUrl" class="fas fa-lg {{ entry.icon }}" ng-class="{ 'text-primary': entry.isDirectory && !isSelected(entry) }"></i>
           <img ng-show="entry.previewUrl" ng-src="{{ entry.previewUrl }}" height="42" width="42" style="object-fit: cover;"/>

src/components/filetree.js

@@ -327,6 +327,12 @@ function FileTreeController($scope, $translate, $timeout, Client) {
     };
 
     $scope.onMousedown = function ($event, entry) {
+        if ($event.button === 2) {
+            $scope.onMouseup($event, entry);
+        }
+    };
+
+    $scope.onMouseup = function ($event, entry) {
         var i = $scope.selected.indexOf(entry);
         var multi = ($event.ctrlKey || $event.metaKey);
         var shift = $event.shiftKey;