SAM_RowHeaderClick wierd problem

I basically have a table with the following action.

On SAM_RowHeaderClick
Call SalModalDialog( dlgDetails, hWndForm)

When I click on the row header I pop-up another window that shows me
detailed information on the row that the person clicked next to.

Now this is the wierd thing.
Let´s say to start off my table window has row 3 selected.
I click on row header for row 10.
dlgDetails pops up with information about row 3 and both row 3 and row
10 are selected. (wierd)

Now I try this.
I add a breakpoint to "Call SalModalDialog( dlgDetails, hWndForm)".
Row 3 is selected.
I click on row header next to row 10.
dlgDetails pops up with information about row 10 and only row 10 is
selected.

This is the expected behavior, but it only occurs when I set a debug
breakpoint! Very wierd.
lParam at the breakpoint shows me value "10".

Anyone have any ideas?

Thank you