The TreeList sets the same width for all columns, but you can change column widths as described below:
You can set custom widths for all or individual columns. Individual settings override common settings. Use the following properties to specify the widths:
In this demo, columns adjust their widths to the content. To enable this feature, set the columnAutoWidth property to true.
The TreeList resizes the adjacent column; the total component width does not change.
The total component width increases or decreases; all other columns maintain their widths.
Use the drop-down list below the TreeList to try both values.
If you do not want users to resize a specific column, disable its allowResizing property.