blast-results-view : preserve the selected (view flag) column value

 ... when switching from results-view tab to sequence-search input tab and back again.
sequence-search.js : update comment for inputIsActive(), which is actively used since 086ea39.
blast-results-view.js : change CP viewRow() to viewRowInit() which computes initial search.viewRow, called in didReceiveAttrs() if this is the first time that search result has been displayed.  viewFeatures() : pass viewRow to showFeatures().
transient.js : showFeatures() : add param view

frontend/app/components/panel/sequence-search.js

@@ -131,8 +131,12 @@ export default Component.extend({
 
   // actions
   actions: {
-    // copied from feature-list, may not be required
+    /** called for single-character input to textarea; similar to
+     * actions.dnaSequenceInput() but that is only called for defined events
+     * (enter / escape), and actions.paste() (paste).
+     */
     inputIsActive(event) {
+      // function name and use is copied from feature-list.
       dLog('inputIsActive', event?.target);
       let text = event?.target?.value;
       if (text) {

frontend/app/components/panel/upload/blast-results-view.js

@@ -77,6 +77,13 @@ export default Component.extend({
       });
     }
 
+    /** search.viewRow will be undefined when this is the first
+     * blast-results-view instance to display this search result.
+     */
+    if (! this.get('viewRow')) {
+      this.viewRowInit();
+    }
+
     /** not clear yet where addDataset functionality will end up, so wire this up for now. */
     this.registerDataPipe({
       validateData: () => this.validateData()
@@ -110,13 +117,15 @@ export default Component.extend({
     }
     return cells;
   }),
-  viewRow : computed('dataMatrix', 'viewFeaturesFlag', function () {
+  viewRowInit() {
     let
     data = this.get('dataMatrix'),
+    /** viewFeaturesFlag is initially true */
     viewFeaturesFlag = this.get('viewFeaturesFlag'),
     viewRow  = data.map((row) => viewFeaturesFlag);
-    return viewRow;
-  }),
+    this.set('search.viewRow', viewRow);
+  },
+  viewRow : alias('search.viewRow'),
 
   /** Result data formatted for upload-table.js : submitFile()
    */
@@ -293,7 +302,7 @@ export default Component.extend({
        */
       nowOrLater(
         viewFeaturesFlag,
-        () => transient.showFeatures(dataset, blocks, features, viewFeaturesFlag));
+        () => transient.showFeatures(dataset, blocks, features, viewFeaturesFlag, this.get('viewRow')));
     }
   },
 
@@ -491,6 +500,8 @@ query ID, subject ID, % identity, length of HSP (hit), # mismatches, # gaps, que
           let feature = transient.pushFeature(features[row]),
               viewFeaturesFlag = newValue;
           transient.showFeature(feature, viewFeaturesFlag);
+          let viewRow = this.get('viewRow');
+          viewRow[row] = newValue;
         }
       });
     }
@@ -515,7 +526,7 @@ query ID, subject ID, % identity, length of HSP (hit), # mismatches, # gaps, que
       }
       let
       validatedData = this.get('dataFeatures'),
-      viewRow = this.get('viewRow'),
+      // or view = this.get('viewRow'),
       view = table.getDataAtCol(t_view),
       viewed = validatedData.filter((r,i) => view[i]);
       resolve(viewed);

frontend/app/services/data/transient.js

@@ -102,12 +102,16 @@ export default Service.extend({
     return blocks;
   },
 
-  showFeatures(dataset, blocks, features, viewFeaturesFlag) {
+  /**
+   * @param view a flag per-feature to enable display of the feature row;
+   * from values of the View checkbox column of the results features table.
+   */
+  showFeatures(dataset, blocks, features, viewFeaturesFlag, view) {
     let
     selected = this.get('selected'),
     // may pass dataset, blocks to pushFeature()
     stored = features.map((f) => this.pushFeature(f));
-    stored.forEach((feature) => this.showFeature(feature, viewFeaturesFlag));
+    stored.forEach((feature, i) => this.showFeature(feature, viewFeaturesFlag && view[i]));
   },
   showFeature(feature, viewFeaturesFlag) {
     let