The LOGFONT's lfHeight member is in logical units, and is being used to
set the yHeight member of CHARFORMAT2 which is supposed to be in twips.

Opening a text file with a NULL terminated character in it was causing
an assertion error after a run was being split due to word wrap.
Windows allows NULL terminated characters to be in the text.

Using Ctrl-RightArrow to move to the start of the next word did not
previously work when at the start of a word.  This means that
Ctrl-RightArrow would not work twice in a row since it should move to
the start of the next word.

The call to GetClientRect returns 0 values for the returned RECT when
called in WM_NCCREATE in on Windows, which ended up causing an assertion
error when Wine's riched20.dll replaces the native version. Moving the
call to WM_CREATE fixes this problem (probably because NCCALCSIZE is
called in between).

There was a missing call to ShowCaret after the caret was created.

The function ME_FindRunInRow uses two parameters to return values by
reference, and treated these parameters as if they were optional except
for the start of the function which set *pbCaretAtEnd without checking
to see if was a NULL pointer.