Expression to evaluate cannot be deleted with Delete key

1. Start debugging an application and interrupt/pause then
2. Add a new expression evaluator, e.g. by drag'n'drop of some variable name from the editor to the "Locals and Expressions" view
3. Select the added expression item
4. Hit the Delete key on the keyboard

Expected: Delete removes the item
Actual: Delete has no effect

Removing the items by using the context menu works.