Problem with values of disabled fields

[Shambonik]

#71 <- An example is here
A value of the disabled field resets after a validation error

Steps:

1. Open Meeting Edit view
2. Change value of the "Meeting Theme" to "Daily" or "Retrospective"
3. Change a start date and time of the meeting (the start must be earlier than the current date time)
4. Push "Save" button

Result
The value of the disabled "Meeting Name" field is equal to the value before changing the "Meeting Theme" field.