Theme CSS sometimes dropped in widgetset mode with web-sockets true
In Wt-3.3.5, with web-sockets true, the theme CSS is sometimes not output in widgetset mode. This can be demonstrated with examples/feature/widgetset using a browser to see which stylesheets get loaded. The behavior appears to be browser and timing-dependent. Sometimes both wt.css and webkit-transitions.css are loaded. Other times, only webkit-transitions.css gets loaded. Although the widgetset example does not make much use of wt.css, I believe the erroneous case is when wt.css is not loaded. With Chrome 48.0.2569.116m under Windows 7, wt.css generally does not get loaded (although I've seen it succeed). With Firefox 44.0.2, wt.css always seems to get loaded...
Attached is a patch to WebRenderer.C which seems to help with the issue. It was lightly tested on a branch from 3.3.5-6-g56eecbd, but should apply cleanly to latest github as WebRenderer.C has not changed since then. The patch would definitely benefit from a careful review.