using "enter" shows calendar form but should not do that

[DB73]

i have a weird thing with my userform.
I placed a textbox on my userform and use it as admin password (Application.Visible = True).
I have an Image2(bttn) to unlock.

but when i enter a text and/or hit the "Enter"bttn on my keyboard a calendar form pops up.
the calendar form should only pop up when entering the cmdbttn18

what could trigger that event?

cmdbtn18 and the pswtxtbx are on the same userform

could it be that its somewhere on the calendar form?

i also tested it with just to place a new textbox on the form, but that has the same problem.

any help would appreciated

 

[DB73]

selecting some labels on the form triggers the event...some with 1 click on the returnbutton, some 2 clicks