Plot crashes with "a is null" on deselecting line

[CSchoel]

When simulating a project with two "pages" of variables and too much data points (yellow warning on the side that number of "variables" was reduced) and then deselecting one of the lines in the plot, a small red box with the text "a is null" appears to the top left of the plot and further deselecting of other variables is not possible anymore.

I wanted to test if this issue persists with the same model when no data point reduction takes place, but could not do that due to #111 .

[njustus]

Can't reproduce this issue on my development box 🤔 May be i fixed this already. I had this bug once..