As mentioned in this post
MigLayout doesn't set the height automatically (at least not in some circumstances) and it has to be done with something like this:
miglayout.setLayoutParams(new AbsListView.LayoutParams(AbsListView.LayoutParams.MATCH_PARENT, 50));
The issue is fixed now in release 0.9.5: http://saynomoo.github.com/maven/saynomoo/mig4android/mig4android/0.9.5/mig4android-0.9.5.jar
There was a bug in the logic when to use the miglayout calculated dimensions and when to use the given LayoutParameter dimensions.
Verified. It now works for me as well.