My desktop app includes a list of elements, each of which should highlight when the mouse is within their bounds. I'm using MouseRegion to make this happen. My MouseRegion widget looks something like this:

MouseRegion(
    child: elementWidget,
    onEnter: () => setState(() {
        highlighedElements.add(elementData);
    }),
    onExit:  () => setState(() {
        highlighedElements.remove(elementData);
    }),
)

Additionally, elementWidget itself is interactive beyond the hover effect, and it's possible to trigger a rebuild based on that interaction. This creates a problem-- if the mouse is hovering over the MouseRegion when elementWidget rebuilds, MouseRegion calls onExit (and would call onEnter immediately after if successful). Because onExit includes a setState() call, an error is thrown for calling setState during a build.

In my case, it's usually possible to add special-case logic to onEnter and onExit to get around this and only conditionally call the setState, but this has been coming up a lot in my app, and I'm guessing it's pretty common in other apps to include a setState in onEnter/onExit. Might it be possible for onEnter and onExit to not be called when the child widget is rebuilt, to avoid this issue?