should-mark-messages-as-read is always true

I have tried the sample project basic/mail with my gmail account via imaps. I just changed

Code:

---

int-mail:imap-idle-channel-adapter

---

to

Code:

---

int-mail:inbound-channel-adapter

---

.

And it seems to me that the attribute should-mark-messages-as-read has no effect, it is always true. Respectively messages are always marked as read on the gmail server.

I am using spring integration 2.0.0.RELEASE

I am not sure i understand the question. There is no attribute "should-mark-messages-as-read" on mail inbound channel adapter simply because it could be used with both IMAP and POP3 and in POP3 there is no way to communicate the SEEN flag to the server, but if IMAP the SEEN flag is always set and if you want to manage it then use "imap-idle-channel-adapter" where such attribute is exposed.
What are you trying to accomplish?

Ok, I see. I was just confused that the attribute was offered by IDE in inbound-channel-adapter but did nothing.

Ok, let me clarify a bit.
You can use inbound channel adapter for both IMAP and POP3, however with POP3 setting 'should-mark-messages-as-read' has no affect.