Merge branch 'dmdimitrov/query-builder-improvements' into mcherkasov/qb-rehydration

Author: igdmdimitrov

projects/igniteui-angular/src/lib/query-builder/query-builder-tree.component.html

@@ -459,7 +459,9 @@ <h6 class="igx-filter-empty__title">
             </div>
         </div>
 
-        <ng-container *ngIf="(!expressionItem.inEditMode && expressionItem.expression.searchTree) || (expressionItem.inEditMode && selectedField?.filters?.condition(selectedCondition)?.isNestedQuery)">
+        <ng-container *ngIf="
+            (!expressionItem.inEditMode && expressionItem.expression.searchTree && expressionItem.expression.searchTree.filteringOperands?.length > 0) ||
+            (expressionItem.inEditMode && selectedField?.filters?.condition(selectedCondition)?.isNestedQuery)">
             <igx-query-builder-tree
                 [style.display]="expressionItem.inEditMode || expressionItem.expanded ? 'block' : 'none'"
                 [entities]="entities"

projects/igniteui-angular/src/lib/query-builder/query-builder-tree.component.ts

@@ -1656,15 +1656,15 @@ export class IgxQueryBuilderTreeComponent implements AfterViewInit, OnDestroy {
         }
     }
 
-
     private init() {
         this.clearSelection();
         this.cancelOperandAdd();
         this.cancelOperandEdit();
 
-        // Ignore values of 'parent' and 'hovered' properties for the comparison
+        // Ignore values of certain properties for the comparison
+        const propsToIgnore = ['parent', 'hovered', 'ignoreCase', 'inEditMode', 'inAddMode'];
         const propsReplacer = function replacer(key, value) {
-            if (key === "parent" || key === "hovered" || key === "ignoreCase" || key === "inEditMode") {
+            if (propsToIgnore.indexOf(key) >= 0) {
                 return undefined;
             } else {
                 return value;