Oh,ya! I remember,the problem with Manga Studio was not fill,the problem was primarily either of the cursor issue or unsatisfactory lasso selection issue,due to which I didn't selected it to qualify my requirnments.Also,it didn't had a large canvas size ,neither alternately had any provision to work on multiple canvas with common eyedropper tool and common unchanged brush/pencil pattern & color,something which is possible with OpenCanvas. For conceptualizing something as big as a car with all profiles(side/front/back) in detail,either you need to work simultaneously on multiple canvases (Opencanvas supports this.)or have to work on a single large size canvas(Photoshop and TV paint Animation(64-Bit only)supports a large size.) Sorry for confussion.I presented slightly incorrect info about Manga studio "Color Fill" issue,becuase I had tested these softwares very long back (allmost 4 to 6 months back)and when these softwares didnot qualified,I didnot remember all of the problems they had,in extreme detail.