[GTK] last item in treegridview is not editable

[Miepee]

Expected Behavior

It should be editable like other items

Actual Behavior

its not editable

Steps to Reproduce the Problem

1. Try to edit the last item (i.e. clicking the checkbox depending on the page) from a treegridview. This can be observed i.e. in the treegridview test in Eto.Test, but also in the Kitchen Sink

Specifications

• Version: 2.7.3
• Platform(s): GTK
• Operating System(s): Arch Linux