I/O in another application?

I recently purchase Growly Notes from the MAS. When I try to create a new note book the dialog hangs up. Neither the Cancel or Save button are responsive. The only why to get out of it is to Force Quit. Went to the support site and downloaded a nice little app to create an app with the system log with app info. I email this into the Growly support and this is the response:

I’ve seen similar things from time to time. For sandboxed apps, due to security reasons, the File/Open and File/Save dialogs are actually separate apps. (Yes, the dialog is put up by another app. It’s insane.) Sometimes the communication between the dialog app and the sandboxed app breaks down. It seems to be random, and restarting the app is sometimes the only way to get out of it. There’s nothing I can do about this; my research has demonstrated that it’s a glitch in the system.

If you’re using an OS older than Yosemite 10.10, it’s more likely to happen. So upgrading to Yosemite is an option in that case, but if you’re already using Yosemite I don’t think there’s anything to be done. Sorry.

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I have never heard of anything like this, and not to except responsibility.
Is this normal?
I this a way to get around Sandboxing?

for sandbox it’s documented that open/save file dialogs are in separated apps.
Avoids a lot of security problems.