Weird "Designer1.cs" files created

Thanks to Zendar's suggestion, this is what I did:

1. Close Visual Studio.
2. Use TortoiseSVN to rename the DataContext1.designer.cs file to DataContext.designer.cs, so the rename is picked up by source control.
3. Opened MyProject.csproj in Textpad.
4. Performed search and replace for DataContext1.designer with DataContext.designer (found 2 instances).
5. Save and close.

Re-opening and building the solution in Visual Studio confirmed this worked. Thanks Zendar!

Information about related files is written in project files (*.csproj). This may fix problem:

1. exclude DataSet designer from project
2. close Visual studio
3. remove Designer1.cs from disk
4. remove Designer.cs from disk (if it exists)
5. start Visual studio
6. open DataSet designer
7. now you should have Designer.cs

Alternative would be to try to change information in *.csproj file and then to rename Designer1 to Designer in all places it occurs. I did not try this, but it may work.