Break out your row labels into another worksheet where the dimension name is IN the viz itself, allowing you to add a tooltip when hovering over the dimension name.
But I am not sure how do I this. I want the mouse over on the same sheet. I tried to create a hover action as well. That is also not working.
Are you using the Java API or wanting to do this with an Action?
I am trying to do this with an Action
It will depend on how your Viz is set up (as one of the methods uses a Dual Axis), but if you look at the Educational Brain Teaser
Although the 'challenge' was to bold a single Row Dim entry...The Dual Axis Method shows how we can make Row Headers into Marks (text marks)...and so can have ToolTips against them. If you are already using dual-axis - the solution from Pooja just uses a MIN(1) Axis for this, and so doesn't need to Dual them (although you have the Header Rows and Bars/Gannts the same width)
Hope this helps.
Mention all your dimensions which ever you want.
In case project description as one dimension ---> click on selected Worksheet and select High light
---Select target highlighting ---selected fields option.