Not all item types allow 'extra value' to be specified for the data source. Are you happy allowing the property for all item types?

I see, do you remember what was the actual rule?

I would say we want the combos to be editable so the completion works and mouse-less operations are easy. This is different option though, that we lack in KProperty but it's wasy to add. It can be called "editable" so we would have:

KPropertyComboBoxEditor::KPropertyComboBoxEditor(const KPropertyListData &listData,
                                                 const KPropertyComboBoxEditorOptions &options,
                                                 QWidget *parent)
   : QComboBox(parent), d(new Private)
{
 ....
   setEditable(d->options.extraValueAllowed || d->options.editable);
   setInsertPolicy(QComboBox::NoInsert);

eg, field datasource can contain =<Complex js > or $<literal string>

Thanks for the reminder Adam.

1. Now I wonder if there's room for a cleanup before we release. Is the '$' prefix used (documented) somewhere?

We have KProperty("value", QString(), tr("Value"), tr("Value used if not bound to a field")) IIRC per my request long ago to simplify the logic.
Special cases: it's called "static-image" for images for backward-compatibility, and for maps we have 3 properties long/lat/zoom.

What do you think about removing the support for the '$' prefix?
If we no longer have the prefix we do not worry about it having no sense e.g. for image elements.

2. The '=' prefix. Looks like it's working, has no equivalent elsewhere in reports and has users already.

Do you see any reason why we would not support the '=' for element types that were not supported before?
That is, for image, text, barcode, maps, web. This patch currently does it.

PS: Maybe in the future we would display invalid column names in some special way on the report. That is, as long as we don't support the '$' prefix, datasource string not having '=' prefix and not leading to existing field is an error worth emphasizing.

Regarding lat/long/zoom, does the map element show you the map for statically provided values (i.e. when is data source is empty)?

In D9941#193148, @staniek wrote:

• GIT_SILENT dataSourceProperty()->setValue -> setItemDataSource
• Remove unnecessary and unused support of static text with $ prefix
• GIT_SILENT Update API for source and format
• GIT_SILENT For docs for loadFromFile

@piggz Please see the changes, I also updated the loadFromFile() which now sets the "value" property.