What do you mean "when using twenty-ten theme"?
I dont use twenty-ten, and I dont have problems with that...

Atahualpa issuing the wordpress code to control the size of the boxes, that is why I asked you to activate the twenty ten theme and test the quickpress box in the dashboard. With twenty ten active, there is no atahualpa code involved and if the quickpress box shows the issue, it is not theme related.

In post #19 you said it was the same with twenty ten so it is not a theme problem.

It could be a problem with the versions of software on your computer. Have you tried on another computer?

In #19 I have said that I haven't changed password.
In #7 I have said that I changed to twenty-ten, then back and tried again atahu, but the theme was only one-line again. The quickpress box always worked regardless of the actual theme.
(I misunderstood you first but I have mentioned it later. Sorry, if not being clear.)