Option to indicate on a curve the epochs where learning rate changed

We often look both at our metric curve and the LR curve to see if an improvement on our metric value happened just after a change in the LR value.
It would be nice if we could have an option to automatically show the epochs at which the LR changed on any chosen curve.
"Indication" could be just a vertical line on the plot at each epoch where the learning rate changed.
It could be implemented with a checkbox under a curve to activate/deactivate LR change indications and a dropdown list to choose the name of the LR tag (so that it would work whatever the LR tag is).
This is particularly useful with ReduceLROnPlateau callback where the LR changes are rare.

No files, tests, or entry points are named. Start by locating the curve rendering and curve controls, then trace how learning-rate tags and epoch data are exposed; done means a selectable LR tag can mark its change epochs on a chosen curve with an on/off control.