slow activation of background window

My app deals with multiple windows, each of which has an associated file name. The file in question is an Excel spreadsheet. I can open multiple windows, with one spreadsheet/file each that is busy calculating in the background. Or I can wait until a window’s Excel file is finished calculating and then open another one, and thus continue to work with the same window over and over again.

The “feature” I am trying to eliminate is the seemingly very slow response of my app to the 1st configuration, i.e., multiple windows. Okay, I create a new window, open up an Excel spreadsheet at which point my app chews on that spread sheet … the calculation may take several minutes depending on the size or cell count of the spreadsheet.

During this calculation process, access to other menu items seems to grind to a halt … such as creating another new window so the app can calculate another spreadsheet, or even just activating a background window.

Even if I completely empty my on became main Handler, same slowness happens.

This seems to be a multi-tasking challenge … I have read in other posts that AppleScript cannot handle multi-tasking and that one potential way around that is to make the spreadsheet calculation a separate app or thread. I am still reading up on this approach. Any fresh ideas on this subject are appreaciated very much.

Thanks in advance