No linuxcnc widgets in designer

Qt 5.9.5 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 7.4.0) on "xcb" 
OS: Linux Mint 19.3 [linux version 4.19.106-rt46-lcnc]

Architecture: x86_64; features: SSE2 SSE3 SSSE3 SSE4.1 SSE4.2

Environment:
  QT_ACCESSIBILITY="1"
  QT_QPA_PLATFORMTHEME="qt5ct"

Features: QT_NO_EXCEPTIONS

Library info:
  PrefixPath: /usr
  DocumentationPath: /usr/share/qt5/doc
  HeadersPath: /usr/include/x86_64-linux-gnu/qt5
  LibrariesPath: /usr/lib/x86_64-linux-gnu
  LibraryExecutablesPath: /usr/lib/x86_64-linux-gnu/qt5/libexec
  BinariesPath: /usr/lib/qt5/bin
  PluginsPath: /usr/lib/x86_64-linux-gnu/qt5/plugins
  ImportsPath: /usr/lib/x86_64-linux-gnu/qt5/imports
  Qml2ImportsPath: /usr/lib/x86_64-linux-gnu/qt5/qml
  ArchDataPath: /usr/lib/x86_64-linux-gnu/qt5
  DataPath: /usr/share/qt5
  TranslationsPath: /usr/share/qt5/translations
  ExamplesPath: /usr/lib/x86_64-linux-gnu/qt5/examples
  TestsPath: /usr/tests
  SettingsPath: /etc/xdg

Standard paths [*...* denote writable entry]:
  DesktopLocation: "Desktop" */home/john/Desktop*
  DocumentsLocation: "Documents" */home/john/Documents*
  FontsLocation: "Fonts" */home/john/.local/share/fonts* /home/john/.fonts
  ApplicationsLocation: "Applications" */home/john/.local/share/applications* /usr/share/xfce4/applications /home/john/.local/share/flatpak/exports/share/applications /var/lib/flatpak/exports/share/applications /usr/local/share/applications /usr/share/applications
  MusicLocation: "Music" */home/john/Music*
  MoviesLocation: "Movies" */home/john/Videos*
  PicturesLocation: "Pictures" */home/john/Pictures*
  TempLocation: "Temporary Directory" */tmp*
  HomeLocation: "Home" */home/john*
  AppLocalDataLocation: "Application Data" */home/john/.local/share/QtProject/qtdiag* /usr/share/xfce4/QtProject/qtdiag /home/john/.local/share/flatpak/exports/share/QtProject/qtdiag /var/lib/flatpak/exports/share/QtProject/qtdiag /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag
  CacheLocation: "Cache" */home/john/.cache/QtProject/qtdiag*
  GenericDataLocation: "Shared Data" */home/john/.local/share* /usr/share/xfce4 /home/john/.local/share/flatpak/exports/share /var/lib/flatpak/exports/share /usr/local/share /usr/share
  RuntimeLocation: "Runtime" */run/user/1000*
  ConfigLocation: "Configuration" */home/john/.config* /etc/xdg/xdg-xfce /etc/xdg /etc/xdg
  DownloadLocation: "Download" */home/john/Downloads*
  GenericCacheLocation: "Shared Cache" */home/john/.cache*
  GenericConfigLocation: "Shared Configuration" */home/john/.config* /etc/xdg/xdg-xfce /etc/xdg /etc/xdg
  AppDataLocation: "Application Data" */home/john/.local/share/QtProject/qtdiag* /usr/share/xfce4/QtProject/qtdiag /home/john/.local/share/flatpak/exports/share/QtProject/qtdiag /var/lib/flatpak/exports/share/QtProject/qtdiag /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag
  AppConfigLocation: "Application Configuration" */home/john/.config/QtProject/qtdiag* /etc/xdg/xdg-xfce/QtProject/qtdiag /etc/xdg/QtProject/qtdiag /etc/xdg/QtProject/qtdiag

File selectors (increasing order of precedence):
  en_US unix linux linuxmint

Network:
  Using "OpenSSL 1.1.1  11 Sep 2018", version: 0x1010100f

Platform capabilities: ThreadedPixmaps OpenGL WindowMasks MultipleWindows ForeignWindows NonFullScreenWindows NativeWidgets WindowManagement SyncState RasterGLSurface SwitchableWidgetComposition

Style hints:
  mouseDoubleClickInterval: 400
  mousePressAndHoldInterval: 800
  startDragDistance: 10
  startDragTime: 500
  startDragVelocity: 0
  keyboardInputInterval: 400
  keyboardAutoRepeatRate: 30
  cursorFlashTime: 1000
  showIsFullScreen: 0
  showIsMaximized: 0
  passwordMaskDelay: 0
  passwordMaskCharacter: U+25CF
  fontSmoothingGamma: 1.7
  useRtlExtensions: 0
  setFocusOnTouchRelease: 0
  tabFocusBehavior: Qt::TabFocusBehavior(TabFocusAllControls) 
  singleClickActivation: 0

Additional style hints (QPlatformIntegration):
  ReplayMousePressOutsidePopup: 0

Theme:
  Platforms requested : gtk3,gnome,generic
            available : gtk2,gtk3,qt5ct
  Styles requested    : qt5ct-style
         available    : bb10dark,bb10bright,cleanlooks,gtk2,cde,motif,plastique,qt5ct-style,Windows,Fusion
  Icon theme          : Mint-Y,  from /var/lib/flatpak/exports/share/icons,/usr/share/icons
  System font         : "Ubuntu" 10

Fonts:
  General font : "Ubuntu" 10
  Fixed font   : "Monospace" 10
  Title font   : "Ubuntu" 10
  Smallest font: "Ubuntu" 10

Palette:
  WindowText: #ff000000
  Button: #ffa0a0a4
  Light: #fff0f0f6
  Midlight: #ffc8c8cd
  Dark: #ff505052
  Mid: #ff6b6b6d
  Text: #ff000000
  BrightText: #ffffffff
  ButtonText: #ff000000
  Base: #ffffffff
  Window: #ffa0a0a4
  Shadow: #ff000000
  Highlight: #ff000080
  HighlightedText: #ffffffff
  Link: #ff0000ff
  LinkVisited: #ffff00ff
  AlternateBase: #ffcfcfd1
  NoRole: #ff000000
  ToolTipBase: #ffffffdc
  ToolTipText: #ff000000

Screens: 1, High DPI scaling: inactive
# 0 "HDMI-2" Depth: 24 Primary: yes
  Manufacturer: 
  Model: 
  Serial number: 
  Geometry: 1920x1080+0+0 Available: 1920x1047+0+0
  Physical size: 509x286 mm  Refresh: 60 Hz Power state: 0
  Physical DPI: 95.8114,95.9161 Logical DPI: 96,96.2526 Subpixel_None
  DevicePixelRatio: 1 Pixel density: 1
  Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

LibGL Vendor: Intel Open Source Technology Center
Renderer: Mesa DRI Intel(R) UHD Graphics 600 (GLK 2)
Version: 3.0 Mesa 20.0.8
Shading language: 1.30
Format: Version: 3.0 Profile: 0 Swap behavior: 0 Buffer size (RGB): 8,8,8