Why did my qty or size column disappear?

When setting up a menu, an important section to check are the column settings.

If a menu has their column settings set to "Auto", this means it will only populate that column if there different values within it.

If you want a column to always show on a menu, set the column to "On" instead of "Auto".

For more information on column settings, here is a How-To and an Expanded Article.

For information on the difference between Auto/On/Off for columns, here is an article that details that.