Loading combo before grid refresh

I have a grid which has few combos. I am using render_complex_sql for loading those combos. But the data in the grid is loaded before the values in combo is loaded due to which ID of the Value is shown instead of the Value. Is there a way to find if all the combos in the grid are loaded before triggering grid refresh?

in the combo.load() method there is a callback function, that allows you to perform the opertion only after the loading process is finished:
https://docs.dhtmlx.com/api__link__dhtmlxcombo_load.html
also there is an onXLE event:
https://docs.dhtmlx.com/api__link__dhtmlxcombo_onxle_event.html
which also allows you to perform some action only after the data is loaded

I wanted to know if there is a method to find if ALL the combos in the GRID has loaded or not so I could call a callback function.

Unfortunately there is no such possibility.