I have a rental where the tenant tells me that the knob keeps coming off the shower assembly. She says that the new tub surround that was installed has made the handle that screws into the cartridge not reach well. She said the new tub surround added about 1-1.5" to the depth of the wall. Can this be solved by getting a longer machine screw? An extension for the cartridge? Or another solution? I would appreciate any help I can get with this issue. It is my concern that if the handyman who did the work added pipe, but the cartridge isn't reaching where the hot and cold water enter, that the whole kit n kaboodle won't work properly. But then I'm not a plumber, but I have experience doing plumbing at my rentals. Had I installed this I'm pretty sure it would be working properly, so I'm not sure what was done wrong. That is why I'm asking here. TIA.