so i was doing some testing and is this what you are trying to have happen, that if you set a font that you dont have it puts up an error window for not installed font?
If so, this is what happens in my test to me setting a font by a name i do not possess in my latest version. Now if you are importing someone elses project and they have it set to a font you do not own i do not think it will throw this error, it should just set the font to Arial. I think if that is what you want then the application would need a rather extensive overhaul. Not saying it cant be done, but honestly only a small handful of people would ever need such a thing added, of course you would probably be one of those peopl as you are building others projects. I will look into this second variant but honestly it is a HUGE amount of work for maybe 5 people opn the whole of the internet would even need such a warning message.