It can be useful to lock the dashboards:
Step 1 : Define a password in the client profile
The password to lock dashboards is defined in the client profile.
You need to go on the Client section > Dashboards > Current lock password.

You need to put the current lock password in order to define a new password.
By default, the password is 1234.
If you want to define a custom password for the client, you need to put:
Current password:1234
New password:Your custom password

Step 2 : Lock the dashboard
To lock a dashboard, you need to edit it and activate the “Lock dashboard” option.

If there is any edition attempts on this dashboard, it will require the password before saving the changes.
If you have forgotten the current password, you need to ask to a Super Admin to unlock it.