Eli,

perhaps I have found another problem with 'bidi-display-reordering' :(

To reproduce:

$ emacs -Q &

Then in the Scratch buffer:

(setq-default bidi-display-reordering t)

and C-M-x

Now: C-f C-x test_wheel.txt (the attached file, which contains 6 long 
lines).

Go to the end of the file: C-End

Now, when one tries to scroll upward the file moving _slowly_ the mouse 
wheel, it seems to 'bounce', i.e. it 'returns' a little back. Only 
persevering, the scrolling continues. Also selecting text with mouse-1 
pressed seems not simple.

May you reproduce the above? Without setting 'bidi-display-reordering' 
seems to work better.

Ciao,
Angelo.