I am using Application Insights Log-Explorer query window to visualize the below query.
Inside the field customDimensions.RemotePC I am string a json payload.
When I try to index the stored json via propery-indexing, i get the value as null. I tried to access it as array that turns null as well.
Could you please help me to access the FirstName property in below diagram.

traces | project test = '{"a": 1}' | project tst = parse_json(test) | extend tst.a. In my case,tst_acolumn has value of1in every row - geobreze