MOVED from ZBXNEXT-8496 subissue 52#

Steps to reproduce:

• Open e.g. graph widget
• Open 'Time period' tab
• Choose Time period->Widget option
• Click on Widget label
• Choose Time period->Custom option
• Click on From or To label

Result: fields are not selected.

Affected places:

• 6.0 and 6.4:

1. Graph widget::Problems -> Problem hosts label
2. Top hosts widget::New column:: Name and Item labels

• Master:

1. Graph widget::Time period-> Widget label
2. Graph widget::Time period::Custom -> From and To labels
3. Top hosts widget::New column:: Name and Item labels