Hello everyone,

I have some problems with the ultragrid,
I'm gonna try to explain what I'm doing and where I'm getting problems.

My ultragrid has a datatable with this structure

Status | CodeMachine | Section | UnitProduction

Status column  is a checkbox type column
and I have configured checkbox header in it.
I'm grouping my rows based on the  "Section" column.

Everything it's ok right here,

If I checked or unchecked the checkbox header,
the rows that are involved in the change also change their state,

And what I want to acomplish is that I need to know How many rows in true status I Have?
To accomplish this, I use AfterHeaderCheckStateChanged event and a method to
loop through all the rows in the grid
and count my rows in true state (State Column),
but I'm getting a strange behavior, for example, in the image 1
I have all the rows in true state, if I uncheck the header checkbox of the status column within groupbyrow called
"Setion: A (4 items)", AfterHeaderCheckStateChanged event is fired and it calls the LoopThroughGrid() method,
the rows within "Setion: A (4 items)" should have the false status,
because I'm unchecking the checkbox header but in the loop I'm getting these rows with still true status.
similarly, if I check the checkbox header again , now that rows have a false state, 
when they should have a state of true because I'm checking the checkbox header.

Why is happening?
How can I solve this?

Maybe using AfterHeaderCheckStateChanged is the problem,if so, wich ultragrid's event
is the most suitable to acomplish this?

I hope to explain myself better much in the images.

by the way, I'm sending to you my code