REAPER won't let me do time selection anymore?? Also, how do you do negative space?

[Robokid]

Hey guys,

I'm in the middle of tracking a band and all of a sudden I can't highlight and area to remove it. Usually, I click and drag and it highlights the area in white, and I can do stuff like right click and select "insert empty space in selection" or "remove selection" etc., but now when I click and drag it won't highlight an area in white...? Any ideas? I'm thinking I probably accidentally changed a setting or something in the preferences box or option drop-down menu.

ALSO!!! I am doing gapless playback for another project, and I want to have negative space between tracks so it doesn't do the slight hiccup before the next track starts (which it does hiccup sometimes with using markers and burning the disk straight from REAPER using the markers as new tracks). Any ideas?

Thanks so much!

Trevor