Every time we change a property of an element we have to hit OK to see the result. If we want to correct it, we have to reopen the properties windows. That's a lot of extra clicking, especially when we are about to make some creative decisions. Not always a quick preview in the properties window is enough to surely tell whether we like the outcome or not.
So my suggestion is to introduce an "APPLY" button in every possible element's properties window, which will update the change we made to the model but won't close the properties window, so we can see the change instantly and keep tweaking properties.
I understand there's a lot of salt associated with comparing Archicad to Revit, but this isn't just a feature of Revit; it's a feature of almost every program BUT Archicad. Windows has had an "APPLY" button in dialog boxes for... well, as long as i've had access to a computer. Archicad's lack thereof is a glaring shortcoming. Please don't be dismissive of ideas as basic as an "APPLY" button just because Revit has one.
I'll try to elaborate on Jack's description, but i think he did a fine job explaining the situation and how an "APPLY" button would help:
Currently, the only way to apply changes you've made in a properties window is to click "OK," which applies the changes you've made *and* closes the window. An "APPLY" button would apply those changes, but keep the properties window open. If you wanted to make another change immediately, this would save you the time of having to re-open the property window and again find the property you were changing.
As to providing an image, please just google "apply button vs ok button." This is a basic feature of modern computer programs.