Go to any course category. Enter management mode. You will be redirected from index.php to management.php.
You will see no way to exit management mode. Breadcrumb leads mo management.php, Manage this category leads to management.php, no button for management mode exit. The only way is go start page and find a category again.
I think in management mode "Manage this category" should be "Stop managing this category" and should lead to couseindex.php?categoryid=cat_id.
As for me "Manage this category"/"Stop managing this category" button in right top of page whould be also useful like "Turn editing on/off" button on course pages