modify thumb size in stash scrollbar accordingly to rendered size
modify thumb size in stash scrollbar accordingly to rendered size

nikibobi/PoESkillTree,MLanghof/PoESkillTree,mihailim/PoESkillTree,brather1ng/PoESkillTree,l0g0sys/PoESkillTree,BlueManiac/PoESkillTreeSource,Yskuma/PoESkillTree,EmmittJ/PoESkillTree,PoESkillTree/PoESkillTree