Have an issue with WingSlot (latest version from the Mod Browser), but I have a workaround though anyway.
I've seen this issue be 'resolved' before, but its still here, so I decided I'd post this.
Wing slots, including visibility switch UI, are unresponsive in "On" or "Subtle" frameskip modes, if it is set to "Off" the problem disappears.
Please note my pc is mega potato, which I think may be part of the issue.
(I think terraria may be sacrificing the ability to interact with the slots in order to attempt 60 fps (completely impossible on this machine, but it helps performance anyways),
not sure if tModloader has all mod code to the back of the frame's call stack or something, that may explain it) (<- I could be full of rubbish)