How to differentiate the GridCombobox column from other columns in non-editable display mode?

You can differentiate the GridComboBoxColumn from other columns by showing the drop down arrow in the display mode. Normally, it is shown only in the edit mode. For this, you need to write the custom style for the GridCell and assign that style to the GridComboBoxColumn.CellStyle property, as follows.

 XAML               

Note: The above custom style is only applicable for the WPF platform. For WinRT and Windows Phone, UWP refer to the following sample links.

The following screenshot shows to differentiate the GridComboBoxColumn from other columns,

Figure 1: Shows drop down arrow for GridComboBoxColumn in display mode

Sample Links:

WPF

WinRT

WP-WinRT

UWP