Prevent selecting no data with RangeSlider

[glasnt]

In addition to preventing the range slider from overlapping, make it so that it always has at least one point of data displayed. Otherwise, all data from graph could disappear.

Only uses the step from the first series on the graph though. Unsure how prudent it would be to get the largest (or smallest) step for all series to use as the limit.

[dchester]

This would be a nice feature to have, but I think this implementation makes too many assumptions -- that the first data series has evenly spaced points; and that the first series has the same granularity as the rest (as you pointed out). There's a possible worst case scenario I'd like to avoid here, where the spacing of the first two points is such that productive zooming on other parts of the graph would be disabled.

[glasnt]

Fair call. I worked this out in my own implementation of this change as well.
Perhaps if there was a way to check if there would be no points being displayed per the filter before it was implemented, but that might be too difficult to implement.