I'm proposing an alternate keyboard navigation for the property grid. While a textctrl-based editor is focused, up and down keys are used to move to the previous or next property, and Enter moves to the next property. This is quite comfortable for inserting data repeatedly through a property grid. Due to application requirements, I'm also skipping category properties while doing this.
Due to TortoiseSVN patch creator, the attached patch (against SVN trunk) also includes my autocompletion modification I've already filed.
Tested on wxMSW 2.8.9.
If you opt to apply this patch, you might want to make this behavior parametric.