LeBlanc Combo

Alright so, I've been playing LeBlanc for a while now, atleast to get her almost to level 5, and I have this one problem about every game, and I'm not sure if it is my error, my computer's error, my internet's error, or the game's error, I'd just like to understand why this happens, so I can fix it :D. Now the problem you might wonder, when I use my combo W-Q-R-E (With quick cast with indicator) I can normally do it correctly, but sometimes my ultimate Q doesn't actually go off. I will W forward, Q my target, and when I press R, It shows the indicator for my W and then I throw my chain, and my second Q wasn't thrown out, reducing my damage greatly. Am I doing the combo too fast? I'm not sure If i even worded this correctly, but I see the indicator for my W whenever trying to pull off this combo about 30% of the time, and can result in the loss of a kill, and/or frustration. Any thoughts on what I can do to fix this and make my combo's smoother? Thanks! :D [slayer-jinx-catface] EDIT : I fixed it, I was using quick cast with indicator and when I used quick cast without indicator my combos were smoother, becuase using quick cast with indicator makes the spell go off when you release the button, not when you press it, so the combos are harder to pull off in a quick manner. Thanks for the responses though :D