While debugging (xdebug), when I click on PHP Debug (next to PHP Console) to hide the panel and show again, the debugging session is lost (e.g. Stack and Context is empty).
Closing the debugging panel ends all debugging sessions/connects. This is intended. The closest thing to hiding while keeping your session would be to drag the panel to the bottom making it as small as possible.
While debugging (xdebug), when I click on PHP Debug (next to PHP Console) to hide the panel and show again, the debugging session is lost (e.g. Stack and Context is empty).