[dusk]

Because it's in a loop. Because of that the dialog is shown for each iteration, BUT as they're very fast and SA:MP only allows one dialog to be open you will probably only see the last one.

pawn Code:

for(new i = 0; i < MAX_FACTIONS; i++)
    {
        if(GroupInfo[i][gActive] == 1)
        {
            format(szDialog, sizeof(szDialog), "%sName: %s - Type: %i - ID: %i",szDialog, GroupInfo[i][gName], GroupInfo[i][gType], GroupInfo[i][gGroupID]-1);
         
        }
    }
    ShowPlayerDialog(playerid, EDITFACTION_LISTFACS, DIALOG_STYLE_LIST, "List of Factions", szDialog, "Select", "Close");