Hi Cesar
Greeting from Syncfusion support
Based on your query we suspect that the comboBox in the column template is not open a popup while clicking the arrow buttons. So, please confirm this is the exact requirement in the grid.
By default, the keyboard arrows are used to change the values inside the box. This is the default behavior of the ej2 ComboBox. Please refer the below demo for your reference,
Please share the below details to provide the solution as soon as possible,
1. If Possible, share the Video Demonstration of requirement.
2. Share the Syncfusion package version.
Regards
Vignesh Sivagnanam