JonP The interval feature now works great, but there are issues with the vertical slider: the arrow buttons are at the upper right and lower left corners of the control instead of aligning with the slider bar the interval markers are strange the interval numbers are at a preset distance from the bar (see pic).
JonP Never mind, I figured it out. The slider control is unhappy when you don't provide a value for width (which it uses for height when vertical). This is what it looks like when width is set to 200:
