The root cause was a mismatch between plot IDs and plot model rows.
This issue would appear when a plot was deleted such that the plot IDs
did not match the plot model row numbers and different plots had
different importance levels. The problem would not occur if the most
recently added plot was deleted.
The plot ID / plot model row mismatch was introduced with the
following commit:
Fixes: add plot then choose new plot does not set \
importance slider
3569f78928
Closes issue #404
By default when a plot is added to the plot model, the
importance value is set to "0" (Minor). However when the new
plot is selected, the importance slider remains set to the value
of the previously selected plot.
Steps to Reproduce:
1. Click add plot (plus sign) button.
2. Select this "New plot".
3. Select "Basic infos" tab and change Plot name to "My Plot".
4. Move Importance slider all the way to the right (Main).
5. Click add plot (plus sign) button.
6. Select this "New plot".
Note that the "New plot" is shown in the plot list pane under
"Minor", but the Importance slider is still all the way to the
right (Main).
This enhancement ensures that the corresponding plot UI importance
slider is also set to the proper plot importance.
