A colleague faced this while running FMW installer on a Linux machine. The display appeared like this

This thread gave a clue that it could have something to do with fonts. So I checked what all fonts related stuff was installed.

[root@someserver ~]# rpm -aq |grep -i font
stix-fonts-1.1.0-5.el7.noarch
xorg-x11-font-utils-7.5-20.el7.x86_64
xorg-x11-fonts-cyrillic-7.5-9.el7.noarch
xorg-x11-fonts-ISO8859-1-75dpi-7.5-9.el7.noarch
xorg-x11-fonts-ISO8859-9-100dpi-7.5-9.el7.noarch
xorg-x11-fonts-ISO8859-9-75dpi-7.5-9.el7.noarch
libXfont-1.5.2-1.el7.x86_64
xorg-x11-fonts-ISO8859-14-100dpi-7.5-9.el7.noarch
xorg-x11-fonts-ISO8859-1-100dpi-7.5-9.el7.noarch
xorg-x11-fonts-75dpi-7.5-9.el7.noarch
xorg-x11-fonts-ISO8859-2-100dpi-7.5-9.el7.noarch
libfontenc-1.1.3-3.el7.x86_64
xorg-x11-fonts-ethiopic-7.5-9.el7.noarch
xorg-x11-fonts-100dpi-7.5-9.el7.noarch
xorg-x11-fonts-misc-7.5-9.el7.noarch
fontpackages-filesystem-1.44-8.el7.noarch
fontconfig-2.10.95-11.el7.x86_64
xorg-x11-fonts-ISO8859-2-75dpi-7.5-9.el7.noarch
xorg-x11-fonts-ISO8859-14-75dpi-7.5-9.el7.noarch
xorg-x11-fonts-Type1-7.5-9.el7.noarch
xorg-x11-fonts-ISO8859-15-75dpi-7.5-9.el7.noarch
[root@someserver ~]#

stix-fonts looked suspicious to me. So I removed that with rpm -e stix-fonts.

That actually fixed the issue. After this the Installer window was displaying fine.