HI, it sounds like a bad update or compile. The trouble with making any changes to this is that sooner or later a update will make that normal then it will be too big.

Not too sure but see if it is normal in : SAFE MODE

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

In Firefox Safe mode these changes are effective:

• all extensions are disabled (about:addons)
• default theme is used (no persona)
• userChrome.css and userContent.css are ignored (chrome folder)
• default toolbar layout is used (file: localstore-safe.rdf)
• Javascript JIT compilers are disabled (prefs: javascript.options.*jit)
• hardware acceleration is disabled (Options > Advanced > General)
• plugins are not affected
• preferences are not affected

TEST.....is the issue still there ? If yes : Please Refresh but do this 1st: Delete your Cookies and Cache and TEST.

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

then

• https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings

TEST....... If no issues then Extensions which need to be added back in 1 at a time and tested ..... Or it is your Profile : Make a new one and test ...:

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

If is your Profile :

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Note: Any customization will revert back to default, you will also need to reinstall Extensions.

Please let us know if this solved your issue or if need further assistance.

Firefox tries to style scrollbars to match your system's theme. I'm not familiar with the options on Linux, but on Mac, the option to have the scroll bar "hide" is an OS-level setting.

KalaDude said

Using Ubuntu 16.04, the scroll bar is incredibly thin and won't pop out unless you rollover the page position indicator which is invisible because the scroll is so thin. Really frustrating.

The official Firefox releases from Mozilla since 46.0 have required GTK 3.4 (three point four) at minimum to run (when most recent Linux distros should have much more current GTK3 versions now like 3.16+) and as a result requires GTK3 themes in use on OS to theme Firefox.

Some Linux distros may have delayed this change in allowing GTK2 themes to still be used with their own Firefox packages until more recently.

You description appears as if you are using a GTK2 theme. Firefox is still usable overall however somethings may be missing like say the scrollbar arrows and Firefox can look unthemed with thin if any scroll bars.

James

dpkg -l libgtk* | grep -e '^i' | grep -e 'libgtk-*[0-9]'

returns

ii libgtk-3-0:amd64 3.18.9-1ubuntu3.3 amd64 GTK+ graphical user interface library ii libgtk-3-bin 3.18.9-1ubuntu3.3 amd64 programs for the GTK+ graphical user interface library ii libgtk-3-common 3.18.9-1ubuntu3.3 all common files for the GTK+ graphical user interface library ii libgtk2-perl 2:1.2498-1 amd64 Perl interface to the 2.x series of the Gimp Toolkit library ii libgtk2.0-0:amd64 2.24.30-1ubuntu1.16.04.2 amd64 GTK+ graphical user interface library ii libgtk2.0-bin 2.24.30-1ubuntu1.16.04.2 amd64 programs for the GTK+ graphical user interface library ii libgtk2.0-common 2.24.30-1ubuntu1.16.04.2 all common files for the GTK+ graphical user interface library

I searched in Synaptic Package Manager to try to figure out how to update to GTK 3.4 but am lost with at least a hundred possibilities, This is a couple week old install of Ubuntu and thus Firefox too, so I am surprised Firefox didn't install any dependent packages it needs to run propperly. I am not sure which package to update. Do you know?

Also I am confused by part of your response you say: "The official Firefox releases from Mozilla since 46.0 have required GTK 3.4 (three point four) at minimum to run (when most recent Linux distros should have much more current GTK3 versions now like 3.16+) and as a result requires GTK3 themes in use on OS to theme Firefox."

I thought more recent version numbers were always higher yet your reply make it seem as though 3.16 is more current than 3.4? ?

3.4 (three point four) is the minimum needed for Firefox since 46.0 to run. Your system appears to have a much more current version of GTK 3.18.9 (three point eighteen point nine).

The GTK 3.16 version is indeed more current as it is a higher number as read it as three point sixteen while 3.4 is low at three point four.

Current versions of GTK3 is actually at 3.22.xx (three point twenty-two) so even 3.16 is old. The old 3.4 version came out in March 2012 if I recall. Most Linux distros Releases in the past few years should have at least 3.12 or 3.14

https://en.wikipedia.org/wiki/GTK https://www.gtk.org/download/linux.php (for reference)

The point is since Firefox now uses GTK3 to run it needs a GTK3 Theme for Firefox to be themed as a GTK2 theme will not work. There may be themes in your package manager or you can use https://www.gnome-look.org/browse/cat/135/

Try to edit or create this file in your home directory and experiment with the slider-width and stepper-size values.

~/.config/gtk-3.0/gtk.css

.scrollbar {
-GtkScrollbar-has-backward-stepper: 1;
-GtkScrollbar-has-forward-stepper: 1;
-GtkRange-slider-width: 15;
-GtkRange-stepper-size: 15;
}