Bookmarks bar missing can't restore it

Question

some time a site opens a pop up window without a bookmarks bar, I can't get it back by re-selecting it so I have to open a new window to get the bookmarks bar back. What is the solution? What is causing this?

Answer 1

Sites can use an optional feature of the window.open() script command to style a pop-up window without some of the standard bars. If you want to limit the ability of sites to do this, you can change a hidden setting:
(1) In a new tab, type or paste '''about:config''' in the address bar and press Enter. Click the button promising to be careful.
(2) In the search box above the list, type or paste '''window_o''' and pause while the list is filtered
(3) Now... the phrasing of these preferences can be a little hard to understand. "true" means the site is disabled (blocked) from turning them off; "false" means the site has the option to turn them off.
To keep access to the Bookmarks Toolbar, you should flip the first one of these from false to true by double-clicking it. I don't know whether you need the menu bar as well; that's the second one.
* dom.disable_window_open_feature.personalbar
* dom.disable_window_open_feature.menubar
Any luck?
Adding these bars may occasionally lead to some of the window content toward the bottom of the page not being visible, if the site sized it tightly and didn't allow space for the extra bars (and turned off the scrollbars). Hopefully that won't be a problem very often, and you should be able to enlarge the window when you need to see more.