I was able to reproduce your problem and it seems that Designer gets confused when you have two plugins for widgets with the same class name.

Make sure:
  • that the name of a class in XML snippet returned by domXml() and the string returned by name() are the same as the widget's class name,
  • that there are no other plugins which name() method returns the same string (you might already have one plugin for AnalogClock widget installed),
  • and finally that you compile your plugin in release mode.


Rename AnalogClock to something like AnalogClockX, update your plugin's code:
Qt Code: 
  1. ...
  2.  
  3. QString AnalogClockPlugin::name() const
  4. {
  5.         return "AnalogClockX";
  6. }
  7.  
  8. ...
  9.  
  10. QString AnalogClockPlugin::domXml() const
  11. {
  12.         return "<widget class=\"AnalogClockX\" name=\"analogClock\">\n"
  13.                ...
  14.                "</widget>\n";
  15. }
  16.  
  17. ...
  18.  
  19. QString AnalogClockPlugin::includeFile() const
  20. {
  21.         return "mycustom.h";
  22. }
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and run:
Qt Code: 
  1. make -f Makefile.Release
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After this you should get a working plugin:
Qt Code: 
  1. <customwidget>
  2.  <class>AnalogClockX</class>
  3.  <extends>QWidget</extends>
  4.  <header>mycustom.h</header>
  5.  <container>0</container>
  6.  <pixmap></pixmap>
  7. </customwidget>
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