yes closed is a better word in that case, I still need to add something in the documentation.
you can't really do that with a button.
The BitmapButton have a toggle state as you can see here but it's not a "mouse over" and you can change the image.
Or if you need your effect, you can use a GeUserArea, we have an example of a fade in the C++ documentation
in Visual Studio, on the properties, below the line Command you have Command Arguments
command : D:\my\path\to\cinema4D\Cinema 4D.exe
Command Arguments : -g_alloc=debug -g_additionalModulePath ="D:\SDK\R21\MyProject\Plugins"
I've marked your thread as a question, be sure to change it to solved (information here)
About your question, we have the information you asked on this manual.
But there's always room to improve so let us know if something is still not clear.
Hello and thanks for the question,
Nice you end up by solving your issue, i would like to point you to our example on Github where you will find the same kind of script but with undo system and cloning the whole track, removing the existing one (if it does)
For your next threads, please help us keeping things organised and clean. I know it's not your priority but it really simplify our work here.
I've added the tags and marked this thread as a question so when you considered it as solved, please change the state :)