Preview compile fails inexplicably

Using latest Fuse, OS X.

When I try to Preview a project (Local or Android), I get that:

Unexpected fatal error! Please report this to us.
Fuse 0.21.0 (build 6650)
Build started: FullCompile
Configuring (3.69s)
Compiling syntax tree
/Users/.../build/Local/Preview14/cache/MainView.g.uno(213.27): E2047: No implicit cast from 'float4' to Fuse.Controls.Rectangle
/Users/.../build/Local/Preview14/cache/MainView.g.uno(213,28,213,74): Error E2047: No implicit cast from 'float4' to Fuse.Controls.Rectangle
(1.49s)

Build completed in 5.19 seconds
1 error
Build ended
fuse: Failed to compile project

The thing is, I kind of see what Rectangle is causing that. If I comment it out, the build will go fine, and then I can uncomment it and the Rectangle will appear. No idea what’s happening here.

Mystery solved: the Rectangle was given a ux:Name of “Background” which seems to be reserved. Changed the name, no more crash.