I don't know what I did, but it does not work anymore... I used the "Reformat into structured CSS" on a minified CSS file and since that moment the "Highlight matching brackets" option stopped working (although it is checked!!).
I upgraded to 4.6.1, but no luck.... -- <http://forum.pspad.com/read.php?2,64140,67886> PSPad freeware editor http://www.pspad.com
