Kontron KTAM3874-pITX - Manual (Page 211)

KTD-S0057-I Page 207 Linux® Programming Examples (DebianTM)
KTAM3874/pITX Software Guide
The figure already implies the absence of the Groupbox border if the GTK+ style is active. With this style the
sample program looks like this (not much better):
The web search refers to QtCurve as a way out of this issue but the download on the target hardware with
sudo apt-get install qtcurve
has no effect. If you analyze the download message (extract):
The following NEW packages will be installed:
docbook-xml docbook-xsl fonts-freefont-ttf gtk2-engines-qtcurve kate-data
katepart kde-runtime kde-runtime-data kde-style-qtcurve kdelibs-bin
kdelibs5-data kdelibs5-plugins kdoctools kwin-style-qtcurve liba52-0.7.4
libattica0 libavformat53 libcddb2 libclucene0ldbl libdirac-decoder0
libdlrestrictions1 libdvbpsi7 libebml3 libfam0 libgif4 libilmbase6 libiodbc2
.
.
.
phonon-backend-vlc plasma-scriptengine-javascript qtcurve qtcurve-i18n
sgml-data shared-desktop-ontologies soprano-daemon ttf-dejavu
ttf-dejavu-extra virtuoso-minimal virtuoso-opensource-6.1-bin
virtuoso-opensource-6.1-common vlc vlc-data vlc-nox vlc-plugin-notify
vlc-plugin-pulse xml-core
you only see the gtk2-engine and KDE TM plugins - the gtk3-engine is absent.
Another method to control the appearance may consist in manually modifying the file ~/.config/Troll-
tech.conf