Hi @BorisT ,
Only the main/master branch is shown on the project dashboard. Also, SonarQube assumes “master” branch is the first branch you scan (we are changing this logic eventually, see [SONAR-11949] Allow different branch to be designated the main branch - SonarSource).
You can choose which is your “main branch” by navigating to the project > Project Settings > Branches & Pull Requests then click on the 
icon to the right of the “master” branch and click on “Rename branch”. It looks like your “Development” branch is the main branch, is that correct? It may be easier to delete your Development branch (in SonarQube), rename master to “Development”, then scan Development branch.
Joe