MaximizeWindow.script

try
    tell application "Finder" to set b to bounds of window of desktop
    try
        tell application (path to frontmost application as text)
            set bounds of window 1 to {item 1 of b, 22, item 3 of b, item 4 of b}
        end tell
    on error
        tell application "System Events" to tell window 1 of (process 1 where it is frontmost)
            try
                set position to {0, 22}
                set size to {item 3 of b, (item 4 of b) - 22}
            on error
                click (button 1 of window 1 where subrole is "AXZoomButton")
            end try
        end tell
    end try
end try