Don't attempt to create a user action record if the trace exceeds the action record size limit.
Use wxAuiNotebook rather than wxListbook for the StreamStatePanel. The wxListbook control was displayed differently under OS X (Cocoa) and GTK - this change should make the display more consistent across platforms (as a bonus, it allows users to move the tabs and split the window).
Modify the TraceViewFrame's view menu so that it uses check items, which are checked if the associated wxWindow is currently shown, and can also be used to hide the associated wxWindow.