It does work for me in a new project as well - in my existing project, I get the crashes, so that's strange. It's a hard crash (as soon as I toggle HDR on in any camera in the scene if a scene color node is also present), and only on Windows. I'll paste the error.log and the Editor.log here, and at the bottom of the editor log are these lines. While not Shader Forge related, googling these lines led me to some other Unity users with similar crashes and the clue to disable HDR:

========== OUTPUTING STACK TRACE ==================
0x0000000140AE677F (Unity) GfxDevice::SetRenderTargets
0x0000000140BC2596 (Unity) GraphicsHelper::SetRenderTargets
0x0000000140B25C33 (Unity) GfxDeviceD3D11Base::GrabIntoRenderTexture
0x0000000140B8F14A (Unity) GfxDeviceWorker::RunCommand
0x0000000140B93E5F (Unity) GfxDeviceWorker::Run
0x0000000140B75060 (Unity) GfxDeviceWorker::RunGfxDeviceWorker
0x00000001411D49CC (Unity) Thread::RunThreadWrapper
0x000000007716652D (kernel32) BaseThreadInitThunk
0x000000007739C521 (ntdll) RtlUserThreadStart
========== END OF STACKTRACE ===========    

Editor.log

https://pastebin.com/kCVpNJSw

error.log

https://pastebin.com/n5MErdWL

It seems to occur if I have cameras in the scene with HDR enabled.

Actually I'm not so sure about this anymore. This might be a problem on Unity's side. :(

Hmm you're right - same deal with other user echo sites. :|

Amazing! :D

Alt+two-finger-tap (don't have to drag) does seem to work, but I had to change my OS X system prefs to allow for two-finger right-click. Normally I have this off (would prefer to keep it that way), but Alt+Control+tap doesn't delete the node either.

Cool, the game is Invisigun Heroes (steam greenlit). It's a local/online multiplayer arena where everyone's invisible - so you have to watch for environmental cues to tell where people are (including yourself). Here's the temporary game one-pager, though I need to add some gifs showing the combat soon:

http://www.sombr.com/invisigun-heroes/

Thanks for the quick turnaround as usual! Hope you don't mind the callout in my game's credits:

So I've been clicking the thumbs up button on replies meaning that I "like" them, and just realized that it means I'm voting on them, which makes no sense. Oops. :)

Visually, you can see a Shader Forge shader in Unity's UI, but it doesn't behave properly like other UI images. It doesn't sort properly according to hierarchy position, and doesn't observe the UI masking methods. Would love to be able to create nifty SF effects on UI sprites. :)