how enable copy paste & start xterm or uxterm

["jindam, vani" <jindam.vani@disroot.org>]

i installed debian sid on userland app.
i have 2 terminals. xterm & uxterm. i have 
installed openbox, jre, mc & palemoon.

i have 2 issues & both of are interrelated:

(1) when i start my vnc session, it 
starts xterm terminal automatically.
which file should i edit to start uxterm? 
(if uxterm is better than xterm?)

(2) how should i enable copy or paste?
right clicking mouse of highlighted text 
(highlighting text using holding left 
mouse button & dragging using pointer 
highlighter) does not work. ctrl+v or 
ctrl+shft+v does not work for pasting.

how do i resolve both issues?

regards,
jindam, vani