The Journal view shows you your activities by time. This allows you to see exactly what you were doing at a particular time. You can expand and collapse entries to see more or less detail.
Notes can be added to entries if you want to record extra information. The note is associated with the particular time, so if the grouping changes the note moves with the time. If you have added notes to entries, the tree is automatically expanded to show the notes.
You can use this window to assign all entries in a particular time range to a group. In the example below, all entries between 1:35 and 2:28 are being assigned to development. Assigning groups by time overrides all other grouping.