bug#7390: 24.0.50; pos-col-row gives incorrect row

[Chong Yidong]

Chong Yidong <cyd@stupidchicken.com> writes:

> I've checked a fix for picture-mouse-set-point into the emacs-23 branch.

Hmm; I took a closer look at your fix, and it doesn't seem quite right.
If you make an abnormally tall header-line, e.g.

(setq header-line-format (propertize "foo" 'face '(:height 5.0)))

then this new code gives the wrong value.  What's needed is to subtract
the pixel Y position of the top of the text area from the pixel Y
position of the top of the window.