How to highlight the Gantt bars when work haven't been start ?

It is weird. Try again changing a data or clean your browser cache

You do not give any workload on this activity, you have just given a duration of 5 days; it is normal that the planning does not change. Please read the friendly manual to undestand how works Projeqtor and especially on various planification modes.

Have you assigned resources on activities with woarkload before ?
On time sheet :
Entering real work ( as planned) you are going to modify the % of progress.
Entering real work ( not as planned ) you are going to modify the % of progress and influence the next planification.
Entering a new left work you are going to modify the % progress and influence the next planification
Projeqtor always calculates plannings considering what has be done and what should be done at any present time to get the better view of the futur.

Or possibly you can define your activities with planning mode "fix duration", so that calculation knows whatr you want to do.
If you left default planning mode "as soon as possible", prpojeqtor expects some assiogned work to correctly plan the tasks.