Feature request: retain legend trace selection when dashboard refreshes

[bijwaard]

Dear Plotly developers,

Thanks for this great plugin, the Plotly panel has some powerful enhancements compared to the Graph panel.

It would be great when the graph/trace selection from the panel legend is kept when there is a dashboard refresh, so that changes in my FFT graph (that refreshes every second) can be better analyzed (see also #78). In my dashboard below, I deselected phase L2 on the Graph panels on the left, which is retained over dashboard refreshes, while in the Plotly panel with FFT on the bottom right the selection is undone on dashboard refresh.

Some info about my dashboard: the FFT pane on bottom right is with plotly panel, RMS and Power on the left and raw signals on top right are with Graph panel, RMS and Power phasors in the middle are with SVG panel, and it uses JSON datasource to fetch measurements from our LV Sensors. With the selector at the top, I can choose the VT and CT that measure 3-phase voltage and current of a building and CT2 measuring a 3-phase inverter. As can be seen from the power phasors pointing to the left, it is sunny at the moment;-)

Kind regards, Dennis Bijwaard