@wp
No, you cannot turn off installation, however you can turn off the re-download of a package. Please see: Options-->Always force download and extract. If the force download is off, and you have an older version of that package in the local repository, things might go wrong.
Anyways can you please open opkman_mainfrm, and put a breakpoint at line 890(tbInstall click) and see where the installation goes wrong. It shouldn't take more then 1-2 minutes, I would do it myself but there is no error at my side.
@po123
Just uncheck the "Always force download and extract", if the zip is available in the local repository, OPM should install it from there.
As for a visual feedback, please check attached image. You can see the following text:
Repository -->the package is available in the central repository
Downloaded --> the package is already downloaded, is available in the local repository
Extracted-->self explanatory
Installed-->self explanatory
Up to date --> the version installed is the same as the one in the central repository or the developers webpage(if available)