While uploading a project, the black window shows the ongoing percentage steps with a kind of gauge meter, wellknown for those users being in programming for long time.
In difference to DOS where the gauge meter line was shown steadily while just the bar length and the percentage changes - in IDE, each new percentage steps is shown in a new line but the window does not scroll up, so you always need to scroll to see the ongoings.
Guess in that "DOS Window" handler, printing the percentage lines just need a 'CR' to follow so the Cursor will just be moved to the start of the line and the next output will then just updates the line .
At final upload, the window gets already a 'CRLF' to show the 'done in xx.xxx seconds' quite properly.
Yep, a small bug only but anything can be improved.