fix(igxHierarchicalGrid): Error is thrown on child grid initialization if Load On Demand is enabled and displayDensity is set.

Author: MKirova

projects/igniteui-angular/src/lib/directives/for-of/for_of.directive.ts

@@ -473,7 +473,8 @@ export class IgxForOfDirective<T> implements OnInit, OnChanges, DoCheck, OnDestr
             }
         }
         const defaultItemSize = 'igxForItemSize';
-        if (defaultItemSize in changes && !changes[defaultItemSize].firstChange && this.igxForScrollOrientation === 'vertical') {
+        if (defaultItemSize in changes && !changes[defaultItemSize].firstChange &&
+            this.igxForScrollOrientation === 'vertical' && this.igxForOf) {
             // handle default item size changed.
             this.initSizesCache(this.igxForOf);
             this._applyChanges();
@@ -1375,7 +1376,8 @@ export class IgxGridForOfDirective<T> extends IgxForOfDirective<T> implements On
             }
         }
         const defaultItemSize = 'igxForItemSize';
-        if (defaultItemSize in changes && !changes[defaultItemSize].firstChange && this.igxForScrollOrientation === 'vertical') {
+        if (defaultItemSize in changes && !changes[defaultItemSize].firstChange &&
+             this.igxForScrollOrientation === 'vertical' && this.igxForOf) {
             // handle default item size changed.
             this.initSizesCache(this.igxForOf);
         }

src/app/hierarchical-grid-remote/hierarchical-grid-remote.sample.html

@@ -1,6 +1,6 @@
 <button (click)='setterBindingChange()'>Set rowSelectable via binding</button>
 <button (click)='setterChange()'>Set rowSelectable via setter on 1st row island</button>
-<igx-hierarchical-grid #grid1 [data]="remoteData" [isLoading]="true" [primaryKey]="'CustomerID'" [autoGenerate]="false" [height]="'800px'" [width]="'100%'" #hGrid [emptyGridMessage]="''">
+<igx-hierarchical-grid #grid1 displayDensity="cosy" [data]="remoteData" [isLoading]="true" [primaryKey]="'CustomerID'" [autoGenerate]="false" [height]="'800px'" [width]="'100%'" #hGrid [emptyGridMessage]="''">
     <igx-column field="CustomerID"></igx-column>
     <igx-column field="CompanyName"></igx-column>
     <igx-column field="ContactName"></igx-column>