-- Due to IHM crash for example a chart can be locked even if nobody is working on it. No more action can be made on this chart (modification, save...).

5 Steps:

* Check anybody is using this chart, else his modification on the concerned chart could be lost  
* Go into the "console magament" part of the GU
* Select the GUI tab
* Find and select
* The chart and unlock it wth the unlock button on the right