Inside Customized style components, you can't use the checkboxs in the blue bars to select all properties or templates. It selects the check box but doesn't actually select any of the elements below them.
Thank you for reporting this issue, it has now been resolved. We are aiming to include any changes that have been made in a future XF release (2.3.0 Beta 4).
Change log:
Fix XF.CheckAll so that multiple checkboxes can be targeted.