I am currently using 5.07 (775) and can report the following: When I open a CSS file, it cannot be edited via HTML/CSS code format or HTML/CSS code compress. Both menu items are not selectable (gray). A workaround is to create a new CSS file and copy the contents of the open file into it. Now the above mentioned menu items can be selected.
In general I have to say that PSPad crashes extremely often for me in the last years or can only be beeanden via an error message. Often when editing HTML files. I have tried both the 64 and the 32Bit version. With the current beta it seems to run more stable, but I had to remove the version again, because the HTML preview does not work here. A window opens but without content. -- <https://forum.pspad.com/read.php?4,78249,78249> PSPad freeware editor https://www.pspad.com