What is command + [or]

Alt + 5 returns an opening square bracket. Command + alt + 5 does not have any effect. So how do I switch between the bookmark fields?

According to your Pukka Quick Reference PDF, Command + [ or ] should allow me to narrow a search to specific fields. This is what I mean when I wrote about switching between bookmark fields. I'm not referring to Pukka's window for posting bookmarks. I am referring to the search bar.

Again, the keyboard command for [ is alt-5 on my MacBook keyboard. Hence, command-alt-5 should yield Command-[. But that has no effect in Pukka. It should, shouldn't it?

I found that on my non-US keyboard layout (localized for German) the Ü and + keys can be used in place of the [ and ] keys on a US-keyboard. Thus, Command-[ in my case is Command-Ü.

Although I now can use these keyboard shortcuts while in the search bar, one can't see what field is the chosen one. I expected the drop-down list to reveal itself upon pressing the keys.