Merge branch '8.2.x' into dmdimitrov/issue6289-8.2.x

Author: kdinev

projects/igniteui-angular/src/lib/grids/grid-base.component.ts

@@ -4667,6 +4667,11 @@ export abstract class IgxGridBaseComponent extends DisplayDensityBase implements
                 return prev + currWidth;
             }, 0);
 
+        // When all columns are hidden, return 0px width
+        if (!sumExistingWidths && !columnsToSize) {
+            return '0px';
+        }
+
         const columnWidth = Math.floor(!Number.isFinite(sumExistingWidths) ?
             Math.max(computedWidth / columnsToSize, MINIMUM_COLUMN_WIDTH) :
             Math.max((computedWidth - sumExistingWidths) / columnsToSize, MINIMUM_COLUMN_WIDTH));

projects/igniteui-angular/src/lib/grids/grid/column-hiding.spec.ts

@@ -620,6 +620,9 @@ describe('Column Hiding UI #grid', () => {
             grid.columnList.forEach((col) => col.hidden = true);
             tick(30);
             fix.detectChanges();
+            grid.columnList.forEach((col) => {
+                expect(col.width).toBe('0px');
+            });
             fixEl = fix.nativeElement, gridEl = grid.nativeElement;
 
             tHeadItems = fixEl.querySelector('igx-grid-header-group');