I am having problems with delay in Reaverb. I am using it with reasynth and I can't see why there is so much latency? I also noticed that some of the Reaverb parameters are missing until I close the Fx window and reopen it. Can anybody help please?

ReaVerb is a convolution reverb. It needs an impulse response which gets convolved with the input (to create the reverb), this process is done via FFT to save CPU power, however FFT (because it works on cuncks of audio) introduces a delay. This delay depends on the block size (Called "max FFT size" in ReaVerb). Higher FFT size = lower CPU usage, but also more delay, while lower FFT size = lower delay, but more CPU. There is also a ZL (zero latency) switch in ReaVerb which enables zero latency processing.

Another option... 

I found this way to work well also. 1. Add Reaverb to your track 2. Click Add, file, and locate the impulse you want. 3. Click Add again and select Trim/Gain/Stretch. this will give you more options to tweak the verb. 4. Adjust the Max Length slider DOWN to suit your taste. I found 20000 is a bit much. I no longer get glitches, pops this way.