P: Blending mode not working and apply changes delay


1- i have a problem that belnding mode not working even i scroll down and i tried most of common solution nothing works.
2- i have another problem which is : if i did any change it dont apply directly while if released the hold of the click it works , like if i keep holding the bar it dont apply any changes and this thing happens in any change. (as u can see in the 2nd pic stroke is at the max amount but it didnt apply cus i was holding the left click while taking the screen shot).
