Frequently Asked Questions   Sections

The Gentleware FAQ is a comprehensive list of questions regarding Poseidon for UML. At this time, third-party plug-ins and products are not covered in this FAQ but we plan to add them in the future. Further information is available from the Poseidon documentation or you can post to our forum.


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FAQ Section: Weird Bugs
  1. WARNING: Couldn't flush system prefs: [...] Couldn't get file lock.
  2. Poseidon crashes/ ends in a Blue Screen on Windows XP/2000
  3. UmlDoc just hangs...
  4. I'm having some strange repaint problems...

    Some Java installations have problems repainting application graphics. This is mainly due to older graphics drivers.

    Here is a text from the JDK release notes that explains the problem. You can set the flags mentioned in Poseidon's start script (poseidon.bat in the bin directory). If you want to start Poseidon using the shortcuts provided by the installer (rather than the bat file), then please edit the option "" found in the "Poseidon for UML.lax" file in Poseidon's installation directory.

    On Microsoft Windows platforms, Java 2D functionality in J2SE 1.4.1 and beyond is implemented using DirectDraw and Direct3D for various offscreen rendering functions. Bugs in some Direct3D drivers have been known to cause problems in previous releases. If you encounter rendering or crashing problems while running a graphical application, consider updating your driver. The latest drivers for a particular card are usually available on the website of your computer, video card, or video chip manufacturer, such as or

    You can also try launching your application with the following command-line flag set:


    This forcibly disables our use of Direct3D and avoids any Direct3D-specific problems.

    You can also try the following flag:
    This flag disables our use of DirectDraw and Direct3D for offscreen images (such as the Swing back buffer).

    If problems persists, try launching the application with this flag:
    This flag disables our use of DirectDraw and Direct3D completely and thus avoids any problems you may be seeing associated with our use of those APIs and their respective drivers on your system.

    For more information about performance-related flags, see Flags for Controlling Performance and Quality, a section in the High Performance Graphics white paper.

  5. How can I fix the toolbar display in the Metal look and feel?
  6. Why does type ahead not work in quicksearch?
  7. Poseidon crashes when trying to change font on Ubuntu Linux

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