Can't access other excel books when userform is open Mac

Hi guys!

I'm currently working on a userform that people have to fill in so that we can track projects that are running. Some people need to access another excel workbook to fill in the userform. I have tried to use:

Please Login or Register  to view this content.

But it doesn't work. There is also no option on the properties window to allow me to make it modeless.

All of the solutions I've seen seem to be for the Microsoft version of excel, but I'm running excel on Mac. I would really appreciate any help on this.

Thanks in advance.

Thanks Trevor, but if that's on the properties window, then no I won't be able to use that.