To double-check, since you are mentioning touchscreen... I assume either you're using a touchscreen Windows device as the client (like a Surface or something similar), or this was a mistaken post meant for the Android or iOS forums.

(I figure I should double-check, because it wouldn't be the first time someone accidentally posted an Android question in the Windows forum or whatever, thinking "oh, the machine I'm streaming *from* is Windows.")

If this is indeed the Windows standalone client, out of curiosity, does it work better if you install Steam on the Windows box you're streaming *to*, and use the 'Stream' button on a game in Steam directly?