I created an extreme performance beta branch for those with weaker PC's. In this branch is the window mode fix. This branch has many graphical features removed and may look worse, but will render at a much higher FPS. If you wish to use it, go to properties and opt into the beta.
I have triggered a build for the main branch, however, it will only contain a minor improvement in performance to retain the overall appearance. In addition to the window fix. It should show up tomorrow as an update.
I am eternally grateful for your participation. Thank you.