Hi Nastaran,
Greetings from Syncfusion.
Query #1: want to have a column with just a toggle button for each row and when I click on the button the cell expands horizontally and other buttons appear
From the query we suspect that you would like to use the detailTemplate and show the custom buttons or elements. Please refer to the below online demo for your reference,
Query #2: I want just that cell expands not the whole column
By default grid does not expand in the cell level but cells can be expanded according the requirements. Please refer to the below tree grid demo,
If the above provided solution does not meet your requirement, then please get back to us with a detailed requirement and scenario details.
Regards,
Pavithra S.