mx_combo_box_append_text() is rather inefficient

[tthef]

mx_combo_box_append_text(), and all the other related functions, will destroy the existing menu and construct a new one in its place, i.e., to populate a combo with 10 items, nine menus with 1, 2, 3, ... 9 items are constructed and destroyed unnecessarily on the way to the 10 item menu. Consequently the time it takes to populate MxComboBox becomes quickly user-perceptible (on 1.8GHz Atom with i915 graphics card a box with 50 items takes several seconds to construct, reaching 45s for 150 items).

A huge improvement can be had by adding an append function that takes a string vector, allowing to add multiple items; I have a preliminary patch for this, though not sure about the function name. Can make a proper patch if this is of interest.

P.S. I realize that pushing 150 items into a combo box makes for terrible UI, but that's an orthogonal issue :)

[thos]

The new API seems reasonable, but is there any way to make mx_combo_box_append_text() more efficient itself?