By default, command buttons have the Auto Sizing attribute set to Grow Only. This attribute is enforced whenever the label text changes, but also when the panel is loaded. When this attribute is enforced, it ensures that the button is wide enough, and high enough, to accomodate its label, including a small buffer area on all four edges.
The idea behind enforcing this attribute at load time is that oftentimes panels are loaded in computers where the default font is different (and possibly much larger) than the font with which the button was saved.
If you don't want this behavior, change the Auto Sizing setting in the Edit Command Button dialog from Grow Only to Never Auto Size.
Luis
NI