You bet. The controls on the Control toolbar are ActiveX controls which, as
you've found, are prone to unexpected behaviours when used on worksheet
objects. I last experienced expected 'growth' in these controls (particularly
the List Box) in Excel 97. I found it was triggered when changing the
worksheet zoom level (I had code which detected the users screen resolution
and adjusted each sheets zoom level accordingly).

Unless you have a specific requirement to use ActiveX controls (such as
triggering multiple events) you might want to use the controls on the Forms
toolbar instead.

These are native Excel controls which have been around since at least Excel 5.
While they each only have one event (OnClick) you can achieve some fairly
sophisticated results without VBA code by linking the controls to ranges.