**You may be able to fix this by adjusting the switch mounting, with the glass tile left intact.** The cover plate should sit against the tile; the toggle or rocker normally projects beyond it.

Turn off the disposal circuit at the breaker and verify that power is off before removing the cover plate. [Leviton’s safety instructions](https://leviton.com/content/dam/leviton/residential/product_documents/instruction_sheet/5050-Instruction-Sheet-English-French-Spanish.pdf) require both steps.

With the cover removed, the cause determines the repair:

- **The switch sits too far forward:** Check for loose mounting screws or excessive spacers behind its metal mounting strap. Adjust the mounting so the switch is firmly supported at the finished wall surface.
- **The electrical box or an extension ring projects beyond the tile:** An electrician should reposition the box or fit the correct extension. Tightening the cover screws will not correct the box depth.
- **Tile or grout interferes with the mounting hardware:** Have the tile installer correct the opening. Avoid prying against or grinding the glass yourself.

**Do not force the plate flat by overtightening its screws**—that can crack the plate or put pressure on the glass. A box extender is intended for a box recessed behind the finished wall; it brings the device forward. [Arlington’s description](https://www.aifittings.com/catalog/miscellaneous/box-extenders) explains that function.

A photo from the side showing the gap, plus one with the cover removed after verifying power is off, would help identify which adjustment you need.