Thank you for the post and I apologize for the delay.
I am able to reproduce and forwarded a report to Testing and Development for review. The steps to reproduce follow:
1. Create a new database (.fp7) with FileMaker Pro 11
2. Added a "Do Nothing" button named "BUTTON" and a single text field.
3. Convert the file with FileMaker Pro 12 or FileMaker Pro 13
4. Change the text field to a calculation field:
GetLayoutObjectAttribute ("BUTTON" ; "objectType" )
Actual Result: "text"
Expected Result: "button"
Afterwards, another named button was created with FileMaker Pro 13 and with the calculation pointed to the new button, the correct result was returned.
This occurs on both Windows and Mac OS X.
That would explain why trying to edit the text in a "pre-12" button object in FM 12 causes the button object to automatically resize on you...Buttons spontaneously change size and position when a text style is applied