Switching between 2 different userforms on 2 different files

I have the following problem: if I want to go from userform 1 (file1) to userform 2 of file2 by means of a command button, this is no problem. But when I want to go back from userform 2 (file2) to userform 1 (file1) file 2 closes which is fine but I get userform 1( file1) neither visible nor open ?

see 2 sample files

https://www.excelforum.com/attachmen...1&d=1646303390
https://www.excelforum.com/attachmen...1&d=1646303390

have tried to upload but it wont works, sorry