1. Start loading Special:Search (optionally with some parameters)
2. Do something, for instance

a) enter the search bar and type something,
b) scroll down to see the results,
c) press the page down or down arrow keys.

I. Expected:
a) I can type uninterrupted;
b) I can scroll continuously;
c) buttons work as normal.

II. Observed: at some point, after the page is done loading (usually many seconds before the initial HTML is shown), the cursor moves to the beginning of the search bar and
a) my typing is interrupted or disrupted, messing up my words;
b) my scrolling is reverted;
c) I have to click outside the search bar for page down to work.

Al this is extremely annoying and it's been going on for a while now.