Update overview.md (#2916)

* Update overview.md

added info about complex properties under "Model Requirements"

* further specification

* Update components/grid/editing/overview.md

Co-authored-by: Iva Stefanova Koevska-Atanasova <[email protected]>

* Update components/grid/editing/overview.md

* Update components/grid/editing/overview.md

---------

Co-authored-by: Dimo Dimov <[email protected]>
Co-authored-by: Iva Stefanova Koevska-Atanasova <[email protected]>

Author: 3 people

components/grid/editing/overview.md

@@ -36,6 +36,7 @@ Adding or editing rows in the Grid sets the following requirements on the Grid m
 
 * The Grid model class must have a parameterless constructor. Otherwise, use the [Grid `OnModelInit` event](slug:grid-events#onmodelinit) to provide a data item instance [when the Grid needs to create one](#item-instances). Optinally, you can also [set some default values](slug://grid-kb-default-value-for-new-row).
 * All editable properties must be `public` and have setters. These properties must not be `readonly`.
+* All complex properties used in the Grid must be instantiated in the [Grid `OnModelInit` event](slug:grid-events#onmodelinit).
 * Self-referencing or inherited properties must not cause `StackOverflowException` or `AmbiguousMatchException` during [programmatic model instance creation](#item-instances).
 
 ## Edit Modes