Ugh... After having a frustrating time with forms having controls that would frequently shuffle themselves in sequence (and often affecting Taborder as well), I learned it's best to avoid "Bring to Front" and "Send to Back". The problem makes itself most apparent if you've got containers and pageframes. The confusing bit is that the you could perform the "Bring to Front" or "Send to Back" and it would appear fine after you save. However, when you reload the form, stuff gets shuffled around and the Taborder settings are often not the sequence you expect. The only way that I was able to "repair" this was to first clear the ZOrder property in everything (the quickest way of this is to open the screen as a table and hacking the Properties directly), then manually change the z-order by cutting and pasting back controls so that they appared in the proper sequence.