I have a fork of a calculator extension originally written by Marc Belmont. It worked up until 27.9.4. Now on 28.1.0 it doesn't. On the error console I get "NS_ERROR_NOT_AVAILABLE: Cannot call openModalWindow on a hidden window" when I open the extension window. After that I get "TypeError: calculator is undefined" or "TypeError: this.calculator is undefined" whenever I try to do anything. Please make openModalWindow work like it used to.
I'm using Palemoon portable on Windows 10.
General discussion, compatibility and contributed extensions.