chore, fixes #128

chore, fixes #126

src/atlasViewer/atlasViewer.constantService.service.ts

@@ -162,7 +162,7 @@ Interactive atlas viewer requires **webgl2.0**, and the \`EXT_color_buffer_float
   /**
    * message when user on hover a segment or landmark
    */
-  public toggleMessage: string = 'double click to toggle select'
+  public toggleMessage: string = 'double click to toggle select, right click to search'
 
   /**
    * observable for showing login modal

src/atlasViewer/atlasViewer.template.html

@@ -24,6 +24,7 @@
         </h5>
       </div>
       <div body>
+
         <div
           *ngIf="onhoverSegmentForFixed$ | async; let onhoverSegmentFixed"
           (click)="searchRegion([onhoverSegmentFixed])"
@@ -35,12 +36,18 @@
         </div>
 
         <div
-          *ngIf="selectedRegions$ | async; let selectedRegions"
+          *ngIf="(selectedRegions$ | async)?.length > 0 && (selectedRegions$ | async); let selectedRegions"
           (click)="searchRegion(selectedRegions)"
           class="ws-no-wrap text-left pe-all mt-0 btn btn-sm btn-secondary btn-block">
           Search KG for {{ selectedRegions && selectedRegions.length }} selected regions
         </div>
 
+        <div
+          class="p-2 text-muted"
+          *ngIf="!(onhoverSegmentForFixed$ | async) && (selectedRegions$ | async)?.length === 0">
+          Right click on a parcellation region or select parcellation regions to search KG for associated datasets.
+        </div>
+        
         <ng-template #noRegionSelected>
           <div
             (click)="searchRegion()"