Icon moving within field

[Scott_Nesbitt]

I have added a checkbox to my table (by showing/hiding a Check Action and an Uncheck Action).  The actions use the "square (Regular)" and "check-square" icons.  The checked icon looks find, but when I uncheck it the square moves to the right, as shown below.

Any ideas on how to keep the icon from moving?  Or do the icons take up space even when hidden?

Here is the first action.  The second action is the same, just reversed logic: