1. No
2. No
3. Maybe in V15.0
4. No

will do fine...

The only thing to solve my problem is, to add a property to the RC, that lets the column, that will be dragged into the GropuBox = Visible. Of course a dragged column, that is still visible, couldn’t drag again into the GroupBox.

1. This info will be saved:  Column order, sort order, group order, column visibility, GroupBox visibility, Column Width, and Alignment.
2. In the help file you will find that you can always load the settings at any time, so it looks like it doesn't matter if columns are added already. I would think you have to add the columns first and then load the settings (I don't know for sure but there will be a support member who can tell you exactly in what order you have to do this).
3. I see that you also delete GroupsOrder and if all works as expected you should be able to load the GroupsOrder from the file as well.
4. One thing you have to check: GroupOrder is cleared when property ShowItemsInGroups is set to True. If you do this after you load the settings, you have no GroupsOrder ! 

I can't think of anything else but it looks like this should work (or it's some kind of bug, or setting that have to be set before or after you load the settings). If you have more time you could upload a test project and I could test this myself. If this isn't helping you, I think you better start a new thread, and if this is a bug I will add it to my collection and if this needs to be added as feature I will add it also

I'm a little bi busy at the moment, to make a full sample. But maybe you understand what I mean, if I explain another way:

1) I have a application that hat a ReportControl.
2) I load the data and enable the GroupBox
3) Then I drop a group in the GroupBox
4) When I do this, the actual ReportControl settings will be saved with the ReportControl.SaveSettings method in a *.ini file.
5) Now I end the application

The problem is that I use two different recordsets, to show into the ReportControl with complete different columns. Because I want so switch between both recordsets during the same session, I have to delete all groups, records and columns, before I load the new recordset.

With ReportControl
    .EditItem Nothing, Nothing
    If .GroupsOrder.Count > 0 Then .GroupsOrder.DeleteAll
    If .Records.Count > 0 Then .Records.DeleteAll
    If .Columns.Count > 0 Then .Columns.DeleteAll
    .Populate
End With

Before I load the new recordset (at application start or by switching) I load the correct ReportControl settings from an *.ini file with the .LoadSettings method. And now the dropped column is not visible. Maybe it is a question of the correct sequence (what doing first), but I first delete all groups, records and columns and so on and the I load the settings from the *.ini file.