I often end up tweaking various tools to avoid having to reach for the mouse as the first action (i.e., to focus on a field before entering text). Following is a modification for auto-focusing the editor textarea in PmWiki. Note: assumption is that the Triad skin is employed.
1) Find pub/skins/triad/wikilib.d/Site.Popup-EditForm and open it in an editor.
2) In that file, there is only one instance of "textarea". It looks like:
(:input e_textarea :)
Make it look like:
(:input e_textarea focus=1:)
3) Save and exit
After that, whenever you open the edit function, the main textarea should already have focus.