Reproduction: 1) Open/start Umbrello. 2) Pushthe "Save" button on the toolbar. 3) Select a folder. 4) Put the text cursor back to the Name text field. 5) Type "foo", without the quotes. 6) Push the "Save" button. 7) Close/stop/exit Umbrello. 8) Open/start Umbrello. 9) Push the "Open" button on the toolbar. 10) Look up the folder, where the "foo.xmi" is expected to be. 11) Curse that the file is "not there". 12) Close the "Open" dialog by pushing the "Cancel" button. 13) Open up a terminal or a file browser and move to the folder, where the "foo.xmi" is supposed to be. 14) Rename file "foo" to "foo.xmi". 15) Push the "Open" button on the toolbar. 16) Look up the folder, where the "foo.xmi" is expected to be. 17) Select file type "*.xmi|Uncompressed XMI files" 18) Enjoy the presence of the "foo.xmi", select it and push the "Open" button.
Opensuse provides several umbrello versions at https://software.opensuse.org/package/umbrello. Which are you using ? I checked this with recent version 18.4.2 and was able to reproduce this behavior only if the file filter in the save dialog was cleared or was set to any type. Can you confirm ?
Actually, this has to do with the mangling of the file filters when the Gnome/Gtk native file dialog is used: https://bugreports.qt.io/browse/QTBUG-78557 Perhaps this could be a user-configurable option to add the .xmi part automatically?
Created attachment 130571 [details] Umbrello's "Save as" dialog with Qt4 The Qt4 version of Umbrello has this setting, as can be seen in the screenshot. Since this dialog is provided by Qt, this seems to be a fundamental problem of Qt5.
(In reply to Ralf Habacker from comment #3) > Since this dialog is provided by Qt, this seems to be a fundamental problem > of Qt5. Looking into the source (https://invent.kde.org/sdk/umbrello/-/blob/master/umbrello/uml.cpp#L1356) , I need to correct that statement. The Qt4 variant uses KFileDialog::getSaveUrl() while the Qt5 variant uses QFileDialog::getSaveFileUrl() which does not support that feature.