This is not installation any more, but opening your existing project for the first time.
The project comes from Lazarus 3 and it uses components not installed yet.
So far, so trivia.
There are 2 matters of beauty:
1) The OPM offers components (in my case install sounds) and instant compiling. After this Lazarus opens with the OPM open and this resulted in freezing the IDE in my case. Restart helped. Just a matter of beauty, because the workaround is self-explaning.
idea: close the OPM window in this re-compile prozess before re-starting the IDE
2) Another offer for installing missing components leads into a circle. See screeshot.
As well a matter of beauty. After having clicked away enough of error-messages (fewer would be nicer), you install them.
idea: halt the started debugging process, if the user clicks this button before going on