The Hybrid Scheduling Mode
just plan it allows to set the global scheduling mode either to "automatic"or to "manual. The hybrid scheduling mode combines the advantages of both alternatives and is generally started out of the automatic mode, which is selected in the Settings dialog and is shown in the plan by the icon 
.
Keep control over certain orders
In some cases, it might be useful to change the global scheduling mode only for one or more jobs so that the planner will be able to manage these important jobs manually, thus making sure that they happen exactly when he wants them to happen and to use the scheduling engine to automatically plan the remaining jobs in an efficient way.
Thus, the hybrid scheduling mode combines the comfort of leaving the planning work completely to an automatic scheduling engine with the ability of taking full control by manually overriding all of the engine's rules.
Switch scheduling mode only for individual jobs
Click 
in the job line of the desired job(s) to schedule them manually, which is indicated by the corresponding icon having turned orange 
. Now, you can manually plan this job and it won't be affected by the scheduling engine any more.
Of course, this also works vice versa. If the global scheduling mode is set to manual, which is indicated by 
and you want to change this for one or some individual jobs, click the icon, it changes to 
and this/these job(s) will be scheduled automatically.