Design Switcher is broken in several areas

[rylin8]

• The Change button opens up an overlay that is sometimes off to the right and does not have customizations applied (the help text and sample doc ID are both in the same area)
• The overlay in the last bullet point can't be closed when clicking outside (tap to close overlay not working)
• Pressing on the Change button again crashes (probably tries to open the same overlay again which shouldn't be allowed since clicking anything outside the overlay should close it)
• The buttons to change to a different branch don't work.

Most of these only apply to squoosh, but some like the Offline mode also apply to non-squoosh.