Ubuntu – Gnome Shell Title Bar won’t change

Download a theme>extract it>Inside it should have something similar to this:

As you can see there's a gtk-3.0 and a metacity-1 folder. These two folders should be in: /home/user/.themes/.

Then open up Gnome Tweak Tool>go to Theme>Window theme>Scroll down to the theme you want.

Log out, and done.

Thanks to the solution linked by user62716: https://bbs.archlinux.org/viewtopic.php?id=167309, let me type it out here.

cd /usr/share/pyshared/gtweak/
sudo gedit gsettings.py

Insert this before line 37:

if schema_name == "org.gnome.desktop.wm.preferences":
    schema_filename = schema_name + ".gschema.xml"

Now it should look like:

def __init__(self, schema_name, schema_dir=None, schema_filename=None, **options):
    if not schema_dir:
        schema_dir = gtweak.GSETTINGS_SCHEMA_DIR
    if schema_name == "org.gnome.desktop.wm.preferences":
        schema_filename = schema_name + ".gschema.xml"
    if not schema_filename:
        schema_filename = schema_name + ".gschema.xml"

Save, and exit. Open Tweak Tool, go to "Theme", and for "Current theme", select your desired theme.