Toolbar buttons not showing on forms

Toolbar buttons suddenly disappeared from all my form applications in Dev mode.
Checking and unchecking Enable Use of Security has no effect.
The only way I can get the buttons to show up is to empty the sec_apps table and the sec_group_apps table.
With the tables empty I can synchronize the application and reconfigure security access, but once the data is saved, once again the buttons disappear.

Thanks.