When a new file is created in a branch but not the trunk, the "Browse the Log Diagram" display seems to get lost. All that shows up is the "Trunk" entry with no info since it doesn't exist at that point.
svn copy file:///svnroot/testing/trunk file:///svnroot/testing/branches/new_file_test
svn co file:///svnroot/testing/branches/new_file_test svndemo
svn add new.txt
Now, using tkcvs to browse svndemo, display the log diagram for new.txt - it will only have the trunk entry, but since that doesn't exist it doesn't go any further.