this simple addon https://www.curseforge.com/wow/addons/lighter-mana-bar was not working as intended for 3.3.5
I changed 1 registry to do what is meant to do. should work perfectly for non-shapeshifting caster. idk about the result when used on druid, haven't tested myself. Feel free to report if it works. cheers!
Here it is the fix: Link
https://i.ibb.co/3r3z8mx/Wo-WScrn-Sh...922-001922.jpg