Description:
After the Mail Merge Wizard is used to setup a data source for a document, the data source cannot be updated and this has several effects:

- The "Refresh" button of the data source toolbar has no effect (if records are added to the underlying data source, they will not appear in the Data Source view in Write). Even reloading the document using File > Reload does not help. The only solution is to close LibreOffice and open it again. This is not a display issue, as the various Mail Merge functions ("Email Mail Merge", "Edit Individual Documents" and "Save Merged Document") will indeed use the original data without taking into account the changes.
- VERY DANGEROUS: While filters can be defined using the data source toolbar of Writer, and the records can be seen correctly filtered in the Data Source of Writer, this has no effect on the actual data used by the "Email Mail Merge" function. This means that if one wants to email the Mail Merge, emails will be sent for all records and not only for the filtered one. This also impacts the "Edit Individual Documents" button, and the "Save Merged Document" button, and the "Print Merged Documents" button. All these functions do not use the whole data set instead of only using the filtered data.
- VERY DANGEROUS: After a data source has been setup for a Writer document, it is not possible to modify it: if one double clicks on a different table in the Data Source view of Writer, while the records of the new table are correctly displayed in the Data Source View, the Mail Merge functions (Email Mail Merge, etc...) will use the data of the original table instead. Closing and reopening LibreOffice writer does not help. The only way to modify a data source is to go to Tools > Options > LibreOffice base > Databases and delete the connection from that configuration dialog.

While the first symptom makes working with LibreOffice's Merge impractical, the last two symptoms are particularly dangerous especially since there is no Preview Window allowing users to double check the records selected. So a user may send the Mail Merge to the wrong people without ever noticing it. I appreciate this is a volunteer-led open-source project but this one really needs to be fixed asap as this is shipping something harmful to users. Making a mass mailing mistake often has serious consequences.

Steps to Reproduce:
1. Create a Writer document
2. Setup a Data Source using the Mail Merge Wizard
3. Modify the source data outside of Writer
4. Filter the data source from Writer and try to Email Mail merge the filtered records 
4. Try to replace the data source in Writer either by double clicking on a different table or by using the Mail Merge Wizard, and try using a Mail Merge Function using the new data source (Email Mail Merge for example) 

Actual Results:
Writer uses stale data when calling the Mail Merge Functions

Expected Results:
Writer should call Mail Merge Functions using up-to-data, whether this means properly refreshing the data source when the Refresh button is clicked, or applying the filters when filters have been defined.


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 7.4.0.0.alpha1+ / LibreOffice Community
Build ID: 089c91b1ad16232f130cb50266732509f83c52eb
CPU threads: 4; OS: Linux 5.18; UI render: default; VCL: kf5 (cairo+xcb)
Locale: fr-FR (fr_FR.UTF-8); UI: en-US
Calc: threaded

Also reproduced on:

Version: 7.3.4.2 / LibreOffice Community
Build ID: 30(Build:2)
CPU threads: 4; OS: Linux 5.18; UI render: default; VCL: kf5 (cairo+xcb)
Locale: fr-FR (fr_FR.UTF-8); UI: en-US
Calc: threaded

For 7.3.4.2 while I couldn't test the "Email Mail Merge" function due to bug #149703, I was able to reproduce the fact that the refresh button does not work and that the data source cannot be modified without fully removing it first from LibreOffice Writer Global options.