There is no way to apply a simple color filter to a group of objects

PROBLEM: There is no way to apply a simple color filter to a group of objects. If I select a bunch of shapes of different colors, any color modification from the "Fill & Stroke..." menu apply to all shapes and changes their colors to the same one. We need to apply color changes that preserve the original colors of the objects, just changing them with the selected color filter. For example TONE, SATURATION, BRIGHTNESS, CONTRAST, COLOR BALANCE, and so on.

SOLUTION: Add a new tab to the "Fill and Stroke..." dialog, called COLOR FILTERS, with 5 sliders: TONE, SATURATION, BRIGHTNESS, CONTRAST, COLOR BALANCE. Those should affect only the color values and parameters of the fills, flat or gradients, and of the strokes. For example if the brightness slider is moved up by 5%, then all the colors of the selected objects will be changed to be brighter by 5%, but change will be applied separately to each object inside the group, changing each color separatedly of the 5%. If two boxes, one red and one black, are selected, then moving the brightness slider up to 10% will change the red box from (255,0,0) to (255,30,30), and the black box color from (0,0,0) to (25,25,25). For the gradients, the color transformation applies separately to each single color steps defined in each gradient. COLOR FILTERS should be optionally applied also to filters if the object has some filter applied. For example a drop shadow should become brighter or toned with greater blue component if the brightness or the tone slider, respectively, are moved up. The contrast slider should make the gradients more or less gradual, and the colors of the objects migrating toward different extremes of the luminance spectrum. The TONE slider can be also expanded in 3 RGB sub-sliders or 4 CMYK sub-sliders, allowing to increase or decrese the percentage of the single color components of the original colors of the selected objects. Objects with gradients or pattern are also affected, and the new modified gradients and patterns will be created and associated with the selected objects without affecting the original ones.

EXPECTED RESULTS: Color manipulation of multiple objects will be finally possible, and it will be possible to select any bunch of objects and make them brighter or darker, more or less saturated, toned toward cold colors or hot colors, and the gradients more or less contrasted, without resetting all objects from their original color to a single color value or gradient.