Hi,
You should always mention which update channel, version and build number of Office/Access you are using. You can see this information on the right side of the File - Account screen or you can press Ctrl+G in Access and paste this in the Immediate Window of the VBA editor, followed by Enter:
?SysCmd(acSysCmdGetFullVersion)
Currently there is a known problem with this kind of effect on forms. It affects version 2606 build 20131.20012 and 20024 in the Current Channel Preview. If you have one of these builds then 1) be aware that this update channel is for testing purposes and b) Microsoft's Access team will fix the problem before version 2606 arrives in the Current Channel, i.e. for production use.
Servus
Karl
Access Forever News DevCon
Access-Entwickler-Konferenz AEK