HTML5 Color Picker
HTML5 supports a new widget exclusively for color picking, via the "color" input that would be incredibly useful in WT. Sadly, it's only supported in HTML5 and in Chrome and Opera.
I understand other things are probably higher priority, but this sort of widget is incredibly useful and furthers WT's HTML5 integration.
Updated by Wim Dumon about 9 years ago
Without trying if it really works, It may work if you load the css and js of spectrum (WApplication::addStyleSheet and WApplication::require), and then call setAttribute on a WLineEdit to set the type to color?
Chrome pops up the color picker if I add this line to hello.C: