Automatic resizing of form control (Scroll Bar)

I had used a form control (scroll bar) in my excel workbook, but it gets resized automatically at times.
What could be done to avoid this? I do have some VBA codes in the workbook, but nothing related to the scroll bar.

Thanks @NeedForExcel for the reply.

I already tried that, but it still gets resized automatically especially when I click the macro option to hide/unhide the scroll bar (form control)

Nope.
The VBA code line that mentions the scroll bar are

ActiveSheet.Shapes("Scroll Bar 12").Visible = False

&

ActiveSheet.Shapes("Scroll Bar 12").Visible = True