3D view keyboard shortcuts/hotkeys (T, L) do not work

[Raven-Singularity]

I am using stock settings, referencing the cheat sheet. It says for the 3D view you can use L to toggle lighting, and T to toggle texturing. Neither of these works in 3D view -- L always switches to Linedef mode, and T always switches to Thing mode. It doesn't make any difference if 2D or 3D view is active for these shortcuts (at least for me).

Is there any way to make the hotkeys work as intended?

Is it caused by me manually clicking the drop-down menu containing Lifedef/Sector/etc. and then the keys L and T are jumping in that list? If so, how do I unselect the drop-down list completely so it doesn't do this? Clicking another field like Zoom percent doesn't have any effect.