I am trying to edit the userChrome.css file to by default hide the tab bar on FF 57 and did it using the following code
#TabsToolbar {
visibility: collapse !important;
}
and I want the tab bar to be visible only when I hover over the nav-bar i.e. the toolbar which contains the address field, navigation buttons, menu button and the like stuff. So, I did tried the following way.
#nav-bar:hover+#TabsToolbar{
visibility: visible !important;
background-color:red !important;
}
I have noted that the hover attribute is not working at all on the #nav-bar because I have noted that even the background color is also not being changed.
Update: In general, css would work like this:
#b
{
visibility: collapse;
}
#a:hover+#b
{
visibility: initial !important;
}<!DOCTYPE html>
<html>
<body>
<toolbar id="a">div a
<p>This para</p>
</toolbar>
<toolbar id="b">div b</toolbar>
</body>
</html>
This worked for me.
This works by instead detecting hover on the entire top navbar