What do you mean "pick up the new check". Perhaps a screenshot would help. I'm envisioning a listbox where all your songs are listed. The user clicks one, then the waveform and its spectrum are displayed in plots. Then the user checks any of 3 possible checkboxes. Finally user selects some operation from popup1 and it runs the callback. So the callback would check the checkboxes before it proceeds. So in the callback:
% Get the state of all 3 checkboxes:
valueOfCheckbox1 = get(handles.chkFreq1, 'Value'); % User wants to process freq band 1.
valueOfCheckbox2 = get(handles.chkFreq2, 'Value'); % User wants to process freq band 1.
valueOfCheckbox3 = get(handles.chkFreq3, 'Value'); % User wants to process freq band 1.
% Now find out which operation the user wants to do.
% Get the item selected in the popup.
selectedPopupItem = get(handles.popOperations, 'Value');
if selectedPopupItem == 1
% Some code to do operation #1
elseif selectedPopupItem == 2
% Some code to do operation #2
elseif selectedPopupItem == 3
% Some code to do operation #4
end
