I totally agree - this has been a problem for a long time.
As it is now, it can only be used for short messages, if you want to be sure that your customer sees everything you have written.
I almost consider it as a bug.
While I like the simplicity of the custom dialog, it is not too difficult to use a popover as a modal dialog. You can hide the button that spawns the popover and use a script trigger to prevent closing if you like as well. This also fits into the single document interface model that FM recommends in order to support the entire platform.
I am happy that someone else is annoyed by that. I will also move toward a popup.
That's a good one! When my spouse removes $20 from my wallet, I "almost consider" her as a thief.
You're right that it's not too difficult, but it does take more time. Also, there are still some solutions running for people who have not yet advanced to v.13. I regret to say that this has been a shortcoming of custom dialogs ever since they graduated beyond "custom message". Personally, I feel pushed over the edge to make a popover when the number of options exceeds the three available buttons, or when the entry options require value lists or field formats that can't be controlled with the three input fields.
FIleMaker make some improvements to Custom Dialog "bugs" in recent years when the commit option became available for all three buttons. IMHO, that would have been the time to address the size and position which have been cross-platform complaints going back to version 8.