It would be good if there was a way to get a tooltip to show on the Row heading column.
There are times where the tooltip to be displayed relates to the entire row and not just a particular block, in these instances it would be very useful to have the tooltip show on the row heading/entity.
At the moment the only options I am aware of are to put the tooltip on a single block/column (which can be somewhat misleading), put it on every block/column (which is a bit ugly/overkill), or show the cube containing the tooltip as a separate 'narrow' column so the comment will display on hover (which even with an alert to highlight the presence of a comment isn't as tidy).
And while we're at it, the ability to control the colour of the tooltip triangle would be great too.