1. A method for restoring an occluded window in application sharing, comprising the steps of: detecting that an unshared window occludes part of all of a shared window; in response to said detecting, (a) creating a first alpha blended image by making the unshared window semitransparent by an alpha blending operation, using a first value for the alpha factor; and (b) creating a second alpha blended image by making the unshared window semitransparent by an alpha blending operation, using a second value for the alpha factor; and restoring the occluded shared window by using the first and second alpha blended images, wherein restoring the occluded shared window by using the two alpha blended images is executed using the formula: 
 backColor=(newColor1*alpha2−newColor2*alpha1)/(alpha2−alpha1) wherein backColor represents the color value of a pixel in the occluded shared window, newColor1 represents the color value of the pixel in the first alpha blended image, newColor2 represents the color value of the pixel in the second alpha blended image, alpha1 represents the value of the alpha factor for generating the first alpha blended image, and alpha2 represents the value of the alpha factor for generating the second alpha blended image.