when I draw an object, let's say a trendline, and I change the color and maybe the style. When I draw another trendline it has the same color and style as the trendline I modified before. Same with rectangles and other objects. Is it somehow possible to set a default color and style for an object or does MT4 always use the parameters of the last modified object for new objects?
It's always been like that as far as I know.
If you use different coloured trendlines and don't want to keep changing colours you can double click a line of the required colour, press Ctrl and drag it. A new line is moved with the mouse and the old line stays where it is.
Yes, unfortunately.. I think I have to live with it. But it's pretty annoying when I change a line to a different color and a different style just to emphasize one thing in a chart. And when I draw another line it is drawn in this color and style. Other chart tools offer a default color and style no matter what the last modifiction was.