<@U78L28DMX> what you want to avoid when dealing w...

# tornadofx

[carlw]

@amanda.hinchman-dominguez what you want to avoid when dealing with graphical apps like this -- simple forms aside -- is to try to keep the model and business logic in sync at all times with what the user sees on the screen. There is of course a relationship (ex rectangle a + line 1 + rectangle b == voltage source a + wire + voltage source b). But you don't want to start putting a lot of the drag and drop operation into the model.

What this means in practical terms is that you may support intermediate states for the UI -- ex dragging -- and execute a final model update onlyu when the UI operation concludes (drop). I've seen attempts to modify model elements along the way that end up in bad states and bugs.