Since other parts of the UI use OpenGL (through Qt), the viewer's context can
sometimes become non-current until the next time it draws. Since the color
processor is created before the main drawing function, the context could
occasionally be non-current causing its creation to fail. Subsequently trying
to use that color processor would trigger a segfault. This commit addresses that
by always making the context current before creating the color processor shader.
itsmattkc
053ea10393