GTK4: Here we go down this rabbit hole again. GTK 4.10 is deprecating tons of functionality with deficient replacement APIs. GtkComboBox is deprecated now suggesting GtkDropDown as a replacement, however GtkDropDown is just a list selection and does not have an editable entryfield version. I haven't completely gone through the changes, but I will attempt to switch to the new APIs where possible to reduce the number of deprecation warnings. This is the first set switching gtk_widget_hide/show() to use gtk_widget_set_visible() instead. This removes about 50 warnings.

/* XPM */
static char * kill_xpm[] = {
/* width height num_colors chars_per_pixel */
"15 15 6 1",
/* colors */
" 	c white",
".	c #5f5f5f",
"X	c gray75",
"o	c black",
"O	c gray40",
"+	c gray70",
/* pixels */
"              .",
" XXXXXXXXXXXX..",
" XoO++++++OoX..",
" XOoO++++OoOX..",
" X+OoO++OoO+X..",
" X++OoOOoO++X..",
" X+++OooO+++X..",
" X+++OooO+++X..",
" X++OoOOoO++X..",
" X+OoO++OoO+X..",
" XOoO++++OoOX..",
" XoO++++++OoX..",
" XXXXXXXXXXXX..",
" ..............",
"..............."};