On Debian, using Code::Blocks svn 9854 from jenslody repository. The 'X' button on editor tabs doesn't work. Clicking on it only focuses the tab.
Double clicking anywhere on the tab has same effect as F2 key - it shows/hides the 'Logs & others' panel.
Evironment Settings -> Notebooks appearance -> Tabs style = 'Default'.
Happens both show close button on 'all tabs', and 'current tab'.