The Index mode is persistent (ie. next time you start H3Viewer, index mode will be the same as last time).
After loading the index the status bar will display something like "Keywords: 10,000\13,000" for 20 seconds -- Meaning 10,000 top level keywords found, 13,000 total keywords if you include all second-level keywords). These figures do not include disambiguator results which can expand inline when you click on some items.
Also in Build 72 we have a slight delay between key entry and performing the query. This allows you to type a full word (if you are quick) before a query is performed. You can switch this delay off or change the delay time in H3Viewer.ini. Currently the default is 300ms, which means if you type s-t-r-i-n-g with less than 300ms between each key press, the query wont happen until you finish typing (300ms after the last letter is pressed). If you type s-t-r then wait > 300ms, then a query is perform on "str". If you type really slowly (>300ms between each key stroke) then you will see a query performed after each keypress. You may prefer to bump this up to 500ms. Set to 0ms to switch off key delay.