Version:           3.4.0 (using KDE 3.4.0, compiled sources)
Compiler:          gcc version 3.4.1
OS:                Linux (i686) release 2.6.10

When I open a new tab and start writing a new address, konqueror deletes what I've just written after one second or so. I think the problem is deletes the contents of the location bar twice: once when it opens the tab (since the location bar is empty), and once again when it finishes 'loading' the new empty tab. It may be my machine being overloaded, but it's annoying anyway. 

This may be related with the way konqueror updates the location bar when changing tabs. It really doesn't care whether the user is writing or not; it changes the path in accordance to the current URL (setting a blank location for a new tab, which is redundant, since a new tab's location bar WILL be empty).