This is a regression. It works correctly in Sarafi 3.2, but not in nightly r41128. Test case is attached. Type a English word in the text box of the test page. The caret should move to right, as that's where the last typed letter is. (FF and IE behaves like this). In Safari, the caret always stays at the very left.
Created attachment 28155 [details] test case
The behavior is correct for Mac OS X. Note that in Firefox, the position (and shape, see bug 22386) of the insertion point changes depending on the active keyboard layout, so that in the attached test case, if one types LTR characters using the U.S. keyboard layout and then changes the keyboard layout to Hebrew, the insertion point moves to the left. In Mac OS X, the position to the left may be indicated by a split caret (see bug 3710), but that does not depend on the active keyboard layout. I don't think this issue warrants two separate bugs (bug 24278 and this one).
*** This bug has been marked as a duplicate of 24278 ***