Headers appear on last column when android:gravity attribute is missing

[viche12345]

When using PinnedSectionGridView, I noticed that removing the android:gravity="center" attribute will break header functionality, where headers will oddly appear on the last column of the GridView.

This is also happening in the sample project, in activity_grid.xml.

Granted, I'm developing on API level 15, which is rather old. Not sure if this could be related.