the following script fails: red background visible.

package require BLT
button .b
frame .f -bg red
blt::table .f .b 0,0
blt::table .  .f 0,0

this one suceeds: button shows!

package require BLT
frame .f -bg red
button .b
blt::table .f .b 0,0
blt::table .  .f 0,0

Claude Fleurey

PS: The "pack" instruction doesn't implement this feature.

Of course it is relevant, the order determines th Z-order, the last widget
created is on top of the others which have been created. If .b is a child
of .f then create it as .f.b, otherwise make sure that the button is on top
of .f by either creating it after or using [raise] or [lower].

Try the same thing using [grid] and see if that works the same way.