There are many annoying problems related with the Maximize native function. For name a few, you cannot maximize one window and not other, or you cannot maximize a window and open a related window not-maximized. There are also many resize related problems.
Replace Maximize function: If you tick this option you will replace the standard "Max" function with a built-in procedure that will resize your window to "fit" the Frame size.
The Frame won't be affected, or SDI windows not inside a Frame.
Any window dependent of a Frame (Either MDI or SDI) will be affected. This could make a special effect, as SDI windows will "pseudo-maximize" to fit the Frame, instead of Windows Desktop.
Force on Windows with no max button: Some windows may not have the "max" button, either by omission or on purpose because you didn't like the default maximize effect. By activating this switch you will force the activation of the "max" button on every window.
Vertical margin (for Toolbar): If you don't use a Toolbar in your program, you should left this field in zero. If you do, you should enter here the height of your toolbar, so it is computed when the child window is pseudo-maximized.
Horizontal offset (for Toolbox): If you don't use a Toolbox or Menu Panel in your program, you should left this field in zero. If you do, you should enter here the width of your panel or toolbox, so it is computed for horizontal offset when the child window is pseudo-maximized.