List: prevent extra scrolling on keypress events on "Select All" checkbox (#31602) (#31623)

Author: dmirgaev

packages/devextreme/js/__internal/ui/list/m_list.edit.decorator.selection.ts

@@ -208,6 +208,7 @@ class EditDecoratorSelection extends EditDecorator {
 
   _selectAllHandler(event): DeferredObj<unknown> {
     event.stopPropagation();
+    event.preventDefault(); // to prevent scrolling on space key press
     this._list._saveSelectionChangeEvent(event);
 
     const { value } = this._selectAllCheckBox.option();

packages/devextreme/js/__internal/ui/list/m_list.edit.ts

@@ -56,7 +56,13 @@ class ListEdit extends ListBase {
         const isInternalMoving = editProvider.handleKeyboardEvents(focusedItemIndex, moveUp);
 
         if (!isInternalMoving) {
-          moveUp ? parent.upArrow(e) : parent.downArrow(e);
+          if (moveUp) {
+            parent.upArrow(e);
+          } else {
+            parent.downArrow(e);
+          }
+        } else {
+          e.preventDefault(); // to prevent extra scrolling
         }
       }
     };