We're updating our home/default page on our chm, and we'd like to add a nice fat Search box directly onto the htm page. Is it possible to do this somehow? Or is the only way to search in a chm is to use the tri pane tab?
Likely possible, but will definitely require a fair amount of "out of the box" thinking. Also will depend on your version of RoboHelp.
RoboHelp 10 (I think) introduced a script named "WebHelp to CHM Converter.jsx". So you use this script to create and package a WebHelp output so it works inside a CHM container. So theoretically, you could use WebHelp output and create a page that may invoke a search, then create a CHM file from that WebHelp.