I suggest you a new feature for "donut charts" (with 2 or more circles, like "browser" and "version" in your example).
I have a real need in this feature. What is it?
When user click on one label at the legend (which has 2 labels: "browser" and "version") this label and circle at the chart display none.
The other data at the chart (i mean the next circles, more outlying) must regroup.
So, if there are 2 same "1.1" version, with "5%" and "7%" at the second circle, after the regroup it must display "12%" in one sector.
I realy need this featere in donut charts and able to buy it, if you do this.