When starting gpkgdep, the installed packages and their dependencies are loaded.
Pressing the cancel stops the loading process and terminates gpkgdep. After loading all installed packages are shown. clicking on the small triangles the required packages are shown:
Note the red warning. pkgbd -F ( from the port sysutils/portupgrade)should be run in order to fix the package db! The red entry means, that the link to the dependent packages is broken here. The middle tab shows the same dependency in the oppsite order:
Here no broken link will appear (although there still broken links!!!). The red warning line warns that some information are missing here. The last tab allows you to mark all packages you do not wan to have any longer:
At the beginning, all packages are not marked (you do not want to have any of them). Checking one of them (here: kde) also checks all required packages and greys them out. The filter allows also to filter them out of the list. After checking all packages you want to have, all packages remaining here unchecked are obviously good candidates for deinstallation.