Hello.
One unfortunate click and my creation tree is gone.
Despite a lot of time wasted searching without success, do you have the solution?
It seems to me that this had already happened to me but no search tool on the site.
Thank you
PS still don't understand this category and label obligation when you're on Solidworks.
A double click on the name of the room effectively hides the tree:
Just double-click in the same place again to make it appear.
Hello;
Normally, the " F9 " function key should make the tree appear again.
Otherwise there is always the solution of restoring your *.sldreg settings (you have backed them up recently, haven't you?)
Edit: In view of @sbadenis's answer, I think I'm off topic (I was thinking of the whole window containing the creation tree... 
That said, regular backup of Solidworks Settings is still a good idea.
Thank you sbadenis
Thank you Maclane
Unfortunately, there was not even the column line separating the room space and the creative space.
The F9 key had no effect.
I found the option to display the creation tree in the options:
Display, User Interface, Feature Manager Tree Area.
Thank you and have a very good week.
It's not on the line but on the name (coin or ace that you have to click)
The symptom is very similar to what I was explaining!
For the yellow bar present only if this option is enabled (but nothing to do with the PB)
I changed the settings. Just in case...
The setting is to add the blocking bar (show in orange) but the double click to hide the function works whether the orange bar is there or not.
No need to turn the feature on or off for that.