Created attachment 147369 [details]
Dummy ODS file that can be used as mail merge data source

This is specific to the kde5 VCL plugin. It works as expected when using e.g. the gtk3 VCL plugin instead.

Version: 6.3.0.0.alpha0+
Build ID: cb52b112c0d44d7a6849f773fd1ee4e863ab91da
CPU threads: 4; OS: Linux 4.18; UI render: default; VCL: kde5; 
Locale: en-GB (en_GB.UTF-8); UI-Language: en-US
Calc: threaded

Steps to reproduce:

1) open a new document in Writer
2) "Tools" -> "Mail Merge Wizard"
3) keep "Use the current document" selected, click "Next"document
4) "Next" (keep "Letter" selected")
5) choose "Select Address list" to add a new data source
6) click "Add"
7) in the file dialog, select an existing Calc sheet with (dummy) mail merge data, confirm


Result: A white window appears, that has the document name in the the title, but no useful content.

Expected result: The window should be shown at all.