Wrong item order in "Select a theme to display for this node"

In the Selectbox the order of items is wrong. My themes are named 2col_aaa, 2col_bbb, 2col_ccc and so on. Today this is a totaly disordered list and difficult to find the correct theme. for e.g. my list looks like 2col_ccc, 2col_aaa, 2col_bbb,... (this is only an example - there are many many more themes...)