AQT makes extensive use of colors for readibility. Many of these colors are non-standard Windows colors, so AQT may not display well when a non-standard Windows Theme is used.
In this case you may wish to select Option > General > Use System Colors. When this option is selected, AQT will use standard Windows colors for many of it's elements. AQT appearance will be slightly different, however it will display with the colors appropriate to the Theme selected.
If AQT detects that you are using a High Contrast theme, it will automatically switch this option on. You can then switch it off if you wish.