Keymap Layer 2 modifications soft crash the client

[allenmhc]

This is my experience using Peg (Peg Pro, if that's relevant) on a lulu keyboard (lily58).

As I'm tweaking the various keymap layers, it seems like if I try to edit Layer 2 specifically (by dragging codes in the UI onto the keyboard map up top) up with new keys, the client freezes up where the tooltip would get stuck, no additional mappings can be edited, etc. There are some things that still work, like navigation on the left, but the mappings get into a really weird state.

The worst part is, it seems like you can actually try to save out the keymap onto the PCB, but if you try (I tried, 2x), it actually saves a corrupt keymap onto the board and from what I can tell requires flashing the entire board again.

[patrickderitter]

Duplicate issue, see #20 for a workaround.