Hi Zoltan:
If you are using Qt, could you check if changing the following does the trick?
Go to the node:
myLeoSettings.leo#@settings-->Qt Gui (appearance)-->@data qt-gui-plugin-style-sheet
Then replace your color in this text:
QTextEdit#richTextEdit {
background-color: white; /* #fdf5f5; A kind of pink. */
color: @text-foreground-body;
selection-color: white;
selection-background-color: lightgrey;
font-family: @font-family;
/* font-family: Courier New; */
font-size: @font-size-body;
font-weight: normal; /* normal,bold,100,..,900 */
font-style: normal; /* normal,italic,oblique */
}
Change the "selection-background-color" to your liking.