RMG v0.3.0 is released. Rosalie's Mupen GUI is a free and open-source mupen64plus GUI written in C++. It offers a simple-to-use user interface.

RMG changelog:
Fix GLideN64 not being able to load texture packs from relative paths (see gonetz/GLideN64#2742)
Fix "Save State Slot" keybindings not working in fullscreen
Fix deadzone percentage being incorrect when set to 0% in RMG-Input
Fix low deadzone value not working in RMG-Input (thank you @porcino)
Fix toolbar being hidden when ending emulation while in fullscreen
Fix zip files with japanese characters in the file name not being able to be opened on windows
Fix ROM Browser not returning to a maximized state when ending emulation
Fix ROM Browser not opening maximized when closing RMG with it maximized
Fix window not being able to be maximized during emulation when scaling is enabled
Fix read-only ROM files not being able to be opened on linux
Remove "Allow Manual Window Resizing" setting due to it being always enabled
Remove Styles tab from settings dialog on windows
Add "Play Game with Cartridge" to context menu when a 64DD disk is selected in the ROM Browser
Add "Open ROM Directory" to context menu in the ROM Browser
Add an On-Screen Display (see the OSD tab in the settings dialog for settings)
Add Theme setting to settings dialog (see Interface -> Miscellaneous, this is a replacement for the previous Styles settings)
Improve error message when opening a zip file fails
Improve tab order and naming in settings dialog

Download: RMG v0.3.0
Source:Here