the faders disappear when moved from their initial position (master faders of the decks, crossfader). Please see the upstream bug.
upstream suggested a workaround. If I use any skin except Deere, the problem goes away.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=d68b84ea00dcc1a0e29d99ce8c07d0c76a72e720 commit d68b84ea00dcc1a0e29d99ce8c07d0c76a72e720 Author: Andreas Sturmlechner <asturm@gentoo.org> AuthorDate: 2020-01-24 21:57:54 +0000 Commit: Andreas Sturmlechner <asturm@gentoo.org> CommitDate: 2020-01-24 22:47:56 +0000 media-sound/mixxx: Fix disappearing fader handles w/ Qt 5.14 Closes: https://bugs.gentoo.org/704176 Package-Manager: Portage-2.3.85, Repoman-2.3.20 Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org> media-sound/mixxx/files/mixxx-2.2.3-qt-5.14.patch | 215 ++++++++++++++++++++++ media-sound/mixxx/mixxx-2.2.3-r1.ebuild | 138 ++++++++++++++ 2 files changed, 353 insertions(+)