I have a new netbook, (1.2Ghz Via C7m processor) and often when I summon do and immediately start typing my characters 'get lost' - Do doesn't see them...
So
1. Summon Do with shortcut
2. immediately start typing
3. Note that Do only catches the last few characters of what I was typing (or none at all).
I just tried it now and the text went in to this box (going as fast as possible I got 'this is' in here and 'a test' in Do), instead of into the Do window. I am using Docky but it happens with Classic, and I presume other themes too.
This is a shame because it slows me down quite a bit - I have to think ' Do. Pause. Action' rather than 'Do. Action' and in the times when I do the latter by mistake I end up with 'Do. wtf? oh. <backspace>. Action'
The time it takes for Do to show up on this machine would be perfectly fast enough if all of my typed input was there when it showed... eg if it started recording input the moment I summoned it and did the UI stuff in the background while still logging my typing. To be perfectly clear, I don't care if the letters don't show up as I type them, as long as they show up all at once when Do has had the time it needs to show me a pretty command window.
As a test, please select some text in your current window (for example, this
sentence), and see if you can still catch Do off guard. Every time you
summon Do, it captures the currently selected text. I think the problem, is
you don't have any selected text, the machinery we use to capture the
selected text pauses a little too long.