Lock the size at a CommandButton

I start a Head Menu with a CommandButton, placed directly at the sheet.
I jump through a lot of tabs, using the Head Menu and a copy of the button is at all sheets.

The sheets are protected, except the cells I need to type data into.
The CommanButtons are locked in the properties too.

My problem is, the CommandButton sometimes (not always) change size, when I click at it.
Height = 33 px
Width = 140,25 px

What can I do, to make the the CommandButtons keep the size?
Or is there a better solution?

Thank you in advance.

Ib

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