Forums Scripts & Popups sonds on connect and on activating windows

I cannot figure out what a certain sound means.
6.31 clean install: test directory containing mirc.exe and a mirc.ini with only one dummy section ([dummy]) so mirc had to complete the ini by itself.. the script contains only this code:
on *:ACTIVE:*: {
echo -a Active window: $active
}
whenever I click into a status, custom, or channel window area, I get a sound. It is the same sound that I get on connect.
in the mirc.ini there is only one entry in the [waves] section:
connect=No Sound
in the tools-options-sounds the option "beep on message: buffer" is checked.
but the help file says:
"Beep on message while in buffer
Makes mIRC beep if someone speaks on a channel while you are scrolling back through lines in the window buffer." (emphasized by me)

1st question:
what does the sound mean when I click into the windows?
2nd question:
why does mirc beep on connect though the mirc.ini says not to beep? (it would also beep without the script)
3rd question:
how can I disable the connect sound without affecting other sounds?

1) If you placed mirc.exe in an empty directory, then you probably have no popups.ini and this is an error beep because there are no popup menus. There is no individual switch for this, if you have sounds enabled you will get this.

2) It's probably the notices sent to you when you connect if you have it set to beep for notices.

3) See above.

as to items 2+3:
RoCk, thanks for the hint! the on notice sound was enabled.
BTW, ist is the 16th item in option n1 (mirc.ini, [options]).
I did not pay attention to the [option] section before, nor did I think of any notices that might come during the connect phase

as to item 1:
you are right, there were no popups. so I made a popup.ini with a single entry:
[mpopup]
test1: echo blabla
in addition, I added this to the script listed in my first posting:
menu status,@testwindow {
test2: echo blabla
}
the popups show up on right click in both windows. but the beep is still there (normal left mouseclick). it ony comes whenever the echo command is used in the onACTIVE code.
I checked my sound options. the buffer option is the only one that is checked. all event sounds are disabled. I even disabled sound in the agent section though I do not use an agent.

this buffer option confuses me: I cannot interpret the beep as "someting happened in the window buffer" because when I use aline instead of echo in a custom window, my speaker remains quiet.
the beep comes only if all these conditions are true:
- onACTIVE code present AND
- echo command within the onACTIVE code that causes an output in the active window AND
- buffer option in tools-options-sounds enabled
confusing.