Congestion graph: congestion metrics hard to read

[ptrd]

Describe the bug
In the graph shown in the tab named "Congestion", ironically the congestion metrics are quite hard to read, because of the following:

• the legend (explaining that purple is the congestion window and olive is bytes in flight) is obscuring the scale and the last section of the congestion graph. In my experience this is always the case, apparently does not depend on the actual graph. Kind of a shame, because a above the legend there is plenty of whitespace to show the legend without hiding anything.
• the values on the scale do not correspond to the grid lines. I understand the grid lines correspond with the #bytes scale on the left, so this could be seen as "intentional". However, the scale at the right seems to be arbitrarily chosen, given the fact that the largest value of the congestion window usually is less the a third of the total scale. If the values for the ticks would be selected in a way that the values at the left are a multiple of the values at the right, the grid lines could serve both scales at the same time!
• it would be nice it the actual values of the congestion-window line could be shown when hovering over it, just like it does with the blue line.

To Reproduce

• Pick any qlog file produced by the interop transfer test case
• Go to the tab "Congestion"

Expected behavior

• The legend should not hide part of the line or scale
• There should be grid lines attached to the scale at the right

Screenshots
See attachments