Bug, feature, or just something I need to program around?

[Alex Tweedly]

In a LC single line field (MacOS), the keys shift-cmd-rightarrow will 
select from the current position to the end of the line, and add that to 
the selection.

BUT if I TAB into the field the cursor is initially at the start of the 
field and the key sequence above will move the cursor to the end 
*without* selecting the characters.

At that point, shift-cmd-leftarrow will move it back to the start, still 
without selecting any characters. But if you do "something else" (e.g. 
left arrow, insert a char, delete a char, ...) then normal behaviour 
resumes. If you click into the field, everything behaves itself.

Feels to me like a bug, but I'd be happy to be corrected.

And, if I need to - any suggestions how I could script around it ?

Thanks,

Alex.