diff --git a/include/znc/Chan.h b/include/znc/Chan.h
index 11a50e32..8ba777f0 100644
--- a/include/znc/Chan.h
+++ b/include/znc/Chan.h
@@ -111,7 +111,7 @@ public:
 	void SetTopicOwner(const CString& s) { m_sTopicOwner = s; }
 	void SetTopicDate(unsigned long u) { m_ulTopicDate = u; }
 	void SetDefaultModes(const CString& s) { m_sDefaultModes = s; }
-	void SetKeepBuffer(bool b) { m_bKeepBuffer = b; }
+	void SetKeepBuffer(bool b);
 	void SetDetached(bool b = true) { m_bDetached = b; }
 	void SetInConfig(bool b) { m_bInConfig = b; }
 	void SetCreationDate(unsigned long u) { m_ulCreationDate = u; }
diff --git a/src/Chan.cpp b/src/Chan.cpp
index b507cb2e..c03967c0 100644
--- a/src/Chan.cpp
+++ b/src/Chan.cpp
@@ -219,6 +219,14 @@ void CChan::SetModes(const CString& sModes) {
 	ModeChange(sModes);
 }
 
+void CChan::SetKeepBuffer(bool b) {
+	m_bKeepBuffer = b;
+
+	if (!m_bKeepBuffer && !IsDetached() && m_pNetwork->IsUserOnline()) {
+		ClearBuffer();
+	}
+}
+
 void CChan::OnWho(const CString& sNick, const CString& sIdent, const CString& sHost) {
 	CNick* pNick = FindNick(sNick);