It works perfectly. But I am still developing this module, so sometimes I have to implement/deploy my custom module again. After this the Layoutdefs folder will be deleted and generated again. So my custom file (to hide the topbutton) will be gone.
I created a module using the Module Builder and it works fine. But if I create a php file to override the subpanel and I will deploy the module again (after I change some other fields/layouts) then all this files in this folder will be gone.
So there is no workaround? the best option is to not use the Module Builder again and make my changes in the Studio?