just done for the main panel (i probably wont dont this for the library explorer unless there are a number of requests for that)
it will be enabled by default for new users only. To activate, click the panel layout button and choose "Thumbnail Browser" and the grouping you want.
For genres, you can create your own .jpg pictures in folder "MusicBee\icons\Genre"
I suggest you size them at 240x240 as i will also use them for when i enable grouping the artwork layout by genre.
Its not 100% complete - i will round off some of the right click handling. Also i am aware it doesnt show all the files with certain combinations of switching the main panel layout and having track browser items selectedhttp://musicbee.niblseed.com/V2_3/MusicBee_Exe_Patched.zip