Currently code history will not be filled with trunk code history by creating a branch. It would be nice if this was possible. This way you can easily do a WinMerge between versions. For example in picture 2 I cannot easily do a WinMerge between 1.11 (trunk) and 1.20 (branch).
While checking the code history detail, I found out that the detail only shows data of the selected (version selector) project_id. So maybe that is the reason why you cannot see this data in that screen. A possible solution is to copy the last trunk code history record as version 1.00 of the branch while creating the branch.
I also found out that trunk code history will not be filled with branch code history after the merge. This is even easier to fix, because you already know to which trunk version you are going to merge. So you can fill originated in project with the trunk project_id and originated in version with the version that is going to arise after merging to trunk.