Problem:    Cannot have expandcmd() give an error message for mistakes.
Solution:   Add an optional argument to give errors. Fix memory leak when
            expanding files fails. (Yegappan Lakshmanan, closes #10071)

Problem:    Vim9: not all code is tested.
Solution:   Add a few more tests.

Problem:    The Athena GUI support is outdated.
Solution:   Remove the Athena GUI code.

Problem:    Test fails with different error.
Solution:   Add argument for :elseif.

Problem:    No error for missing expression after :elseif. (Ernie Rael)
Solution:   Check for missing expression. (closes #10068)

Problem:    Cannot force getting MouseMove events.
Solution:   Add the 'mousemoveevent' option with implementaiton for the GUI.
            (Ernie Rael, closes #10044)

Problem:    Redrawing a vertically split window is slow when using CTRL-F and
            CTRL-B.
Solution:   When deciding on USE_REDRAW bail out if scrolling more than three
            lines. (issue #8002)

Problem:    Using :normal with Ex mode may make :substitute hang.
Solution:   When getting an empty line behave like 'q' was typed.
            (closes #10070)

Problem:    'wildignorecase' is sometimes not used for glob().
Solution:   Also use 'wildignorecase' when there are no wildcards.
            (closes #10066, closes #8350)

Problem:    Memory allocation failures for new tab page not tested.
Solution:   Add tests with failing memory allocation. (Yegappan Lakshmanan,
            closes #10067)