Win10 - Quadro 4000
Broken: 2.78 RC1
Worked: 2.77 with old grease pencil layers
Short description of error
With the new color palette layers of grease pencil, the color tint of the grease pencil layer is no more active when painting and the color of the stroke is visible only when the mouse is released.
Exact steps for others to reproduce the error
Create a grease pencil layer, change the tint color to anything but black, change the tint factor to 1 and draw a stroke, the stroke will be black until the button is released.
or open the attached file and draw a stroke to see the issue.