That's fine, I know SF can have issues from time to time.
Which texture did you use for the switch? It must be one which begins with SW1 or SW2 for it to animate. Also is the switch on a two-sided line? If it is, make sure no other parts of a line have a switch texture, since the game will only animate one of the parts (upper or lower) and it might the part which is not visible. The map checking functions can usually find this particular issue.
The line types shown in the browser are the ones the engine support. In Vanilla Doom the options for shootable types (abbreviated to G1 and GR) are very limited. If your wad targets the Boom standard (which most source ports support, but not vanilla Doom or chocolate-doom) then there are more linetypes available, plus there is a thing called "Generalized LineTypes" offers a lot of flexibility in how a door or lowering floor (etc) is triggered, and Eureka fully supports these generalized linetypes....
The main difficultly for free look is the current method of querying what the mouse pointer is pointing at in the 3D view -- it requires writing new code to do this, and it will be quite a lot of work. A minor difficulty is how the sky is drawn, looking upwards you would see ugly breaks in the sky -- so the sky drawing parts need to draw some horizontal polygons to prevent that (currently the sky is drawn by purely vertical polygons). Also drawing things might be a bit weird, we don't draw a full...
updated the info in AUTHORS.txt and README.txt
Version bumped to 2.00
moved CHANGES.txt --> changelogs/127.txt
I just pushed a few commits to master which hopefully solves these crashes, please test when you can.