When the quadrant tool is selected, and if you haven't unselected the "quadrant statistics" preference in the preferences dialog, then FlowJo will track a cross hair over the graph window. It will also continuously update the frequencies of events within each quadrant (these frequencies are the percentage of events falling within each quadrant, with respect to the events that fall in the current subset. Thus, the four frequencies add up to 100%).

The live quadrant statistics are shown ONLY while you track the mouse. Once you click to select the quadrant position, FlowJo will create four rectangular gates as subsets of the current population. FlowJo names the gates according to the parameters and each quadrant position. A quadrant gate is therefore named as "Q: parmX± parmY±", where parmX and parmY are the X and Y parameters, respectively, and "±" will reflect whether the quadrant is the higher ("+") or lower ("-") quadrant for that parameter.  (If necessary, FlowJo may truncate the names of the parameter stains such that the overall gate names are not too long).

Once you have created the quadrant gates, each one behaves as a separate subset gate. You can independently move any single quadrant gate (note that then you will no longer necessarily cover all events in the plot!). If you want to move all four quadrant gates together, then shift-select each of the quadrants in the graph window. Now you can move them to a new position.  You may also click on the central, shared vertex of quadrants to move all four simultaneously.

When you have quadrant gates on a graph, they cover the entire area of the graph at all times. This means that other gates may be "below" these gates. To select other gates, press the command-key while clicking in an area of the graph: this will select the next gate in the same area of the mouse.