Disk Usage Analyzer hover-text behaviour

Cross posted from the Ubuntu MATE bug.launchpad (link at bottom of description)

I have been using Ubuntu GNOME 16.04.5 and Ubuntu MATE 18.04.1 on two different systems. I noticed different behaviour between GNOME Disk Usage Analyzer and MATE Disk Usage Analyzer, with the latter having less predictable behaviour with respect to the "tooltip" or "hovertext" (sorry I don't know the correct term) which appears when you are hovering over the ring chart.

When hovering over the grey circle in the centre, sometimes the current folder name and disk usage is displayed in a black label while the subordinate directory names are displayed as a grey label with a leader line to the ring representing that directory. Other times, nothing is displayed. Strangely, if you keep your mouse cursor slowly moving within a ring it will ensure that the grey labels appear. They will disappear immediately if the mouse stops moving. I am not certain what provokes the black labels to appear as this seems random to me. This was not the case with my experience on GNOME Disk Usage Analyzer and I suspect is contrary to what most users would want to happen.

I recommend that this be fixed so that the labels appear when the mouse hovers or moves over a ring.

Current Behaviour

Example of no labels appearing when hovering over a ring. current

example with labels while moving mouse continuously. current2

Linux Distribution

Ubuntu MATE 18.04.1

Link to downstream report of your Distribution

Ubuntu MATE bug entry

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mate-desktop / mate-utils