diff --git a/lib b/lib
index 439b54952..a7725f27b 160000
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit 439b5495237a2364f534b669901f9a0dd7df18da
+Subproject commit a7725f27b88b9db7cabcd8e958b6efb665ef53c8
diff --git a/src/ngscopeclient/BERTDialog.cpp b/src/ngscopeclient/BERTDialog.cpp
index c3ec01f25..b13ec7fd4 100644
--- a/src/ngscopeclient/BERTDialog.cpp
+++ b/src/ngscopeclient/BERTDialog.cpp
@@ -120,7 +120,10 @@ bool BERTDialog::DoRender()
 			}
 
 			HelpMarker(to_string(m_bert->GetCustomPatternLength()) +
-				" -bit pattern sent by all channels in custom-pattern mode");
+				" -bit pattern sent by all channels in custom-pattern mode.\n"
+				"\n"
+				"Note that this includes the reference clock output on the ML4039, if\n"
+				"configured in SERDES mode.");
 		}
 	}
 
@@ -137,10 +140,17 @@ bool BERTDialog::DoRender()
 			m_txPattern = m_bert->GetGlobalCustomPattern();
 			m_txPatternText = to_string_hex(m_txPattern);
 		}
+		HelpMarker("Select which clock to output from the reference clock output port");
 
 		ImGui::SetNextItemWidth(width);
 		if(Dialog::Combo("Data Rate", m_dataRateNames, m_dataRateIndex))
+		{
 			m_bert->SetDataRate(m_dataRates[m_dataRateIndex]);
+
+			//Reload refclk mux setting names
+			m_refclkNames = m_bert->GetRefclkOutMuxNames();
+		}
+		HelpMarker("PHY signaling rate for all transmit and receive ports");
 	}
 
 	return true;
diff --git a/src/ngscopeclient/BERTInputChannelDialog.cpp b/src/ngscopeclient/BERTInputChannelDialog.cpp
index 5a328b8fe..c7aaa2599 100644
--- a/src/ngscopeclient/BERTInputChannelDialog.cpp
+++ b/src/ngscopeclient/BERTInputChannelDialog.cpp
@@ -143,6 +143,7 @@ bool BERTInputChannelDialog::DoRender()
 		ImGui::SetNextItemWidth(width);
 		if(ImGui::Checkbox("Invert", &m_invert))
 			m_channel->SetInvert(m_invert);
+		HelpMarker("Inverts the polarity of the input");
 	}
 
 	if(ImGui::CollapsingHeader("CDR", defaultOpenFlags))
@@ -151,6 +152,9 @@ bool BERTInputChannelDialog::DoRender()
 			auto lock = m_channel->GetCdrLockState();
 			ImGui::Checkbox("Lock", &lock);
 		ImGui::EndDisabled();
+		HelpMarker(
+			"Indicates whether the clock recovery loop and PRBS checker are locked to incoming data.\n"
+			"If not locked, no measurements can be made.");
 	}
 
 	if(ImGui::CollapsingHeader("Pattern Checker", defaultOpenFlags))
@@ -158,6 +162,8 @@ bool BERTInputChannelDialog::DoRender()
 		ImGui::SetNextItemWidth(width);
 		if(Dialog::Combo("Pattern", m_patternNames, m_patternIndex))
 			m_channel->SetPattern(m_patternValues[m_patternIndex]);
+
+		HelpMarker("Expected PRBS pattern");
 	}
 
 	if(ImGui::CollapsingHeader("Measurements", defaultOpenFlags))
@@ -172,6 +178,7 @@ bool BERTInputChannelDialog::DoRender()
 			auto state = m_parent->GetSession().GetBERTState(m_channel->GetBERT());
 			state->m_horzBathtubScanPending[m_channel->GetIndex()] = true;
 		}
+		HelpMarker("Acquire a single horizontal bathtub measurement");
 
 		if(ImGui::Button("Eye"))
 		{
@@ -182,6 +189,7 @@ bool BERTInputChannelDialog::DoRender()
 			auto state = m_parent->GetSession().GetBERTState(m_channel->GetBERT());
 			state->m_eyeScanPending[m_channel->GetIndex()] = true;
 		}
+		HelpMarker("Acquire a single eye pattern measurement");
 	}
 
 	return true;
diff --git a/src/ngscopeclient/BERTOutputChannelDialog.cpp b/src/ngscopeclient/BERTOutputChannelDialog.cpp
index 2e02f3a03..3d4d7e8c5 100644
--- a/src/ngscopeclient/BERTOutputChannelDialog.cpp
+++ b/src/ngscopeclient/BERTOutputChannelDialog.cpp
@@ -158,6 +158,11 @@ bool BERTOutputChannelDialog::DoRender()
 		ImGui::SetNextItemWidth(width);
 		if(Dialog::Combo("Pattern", m_patternNames, m_patternIndex))
 			m_channel->SetPattern(m_patternValues[m_patternIndex]);
+
+		if(!m_channel->GetBERT()->IsCustomPatternPerChannel())
+			HelpMarker("Pattern to drive out this port.\nNote that all ports in \"custom\" mode share a single pattern generator");
+		else
+			HelpMarker("Pattern to drive out this port.");
 	}
 
 	if(ImGui::CollapsingHeader("PHY Control", defaultOpenFlags))
@@ -165,20 +170,25 @@ bool BERTOutputChannelDialog::DoRender()
 		ImGui::SetNextItemWidth(width);
 		if(ImGui::Checkbox("Enable", &m_enable))
 			m_channel->Enable(m_enable);
+		HelpMarker("Enable the output driver");
 
 		ImGui::SetNextItemWidth(width);
 		if(ImGui::Checkbox("Invert", &m_invert))
 			m_channel->SetInvert(m_invert);
+		HelpMarker("Invert polarity of the output");
 
 		ImGui::SetNextItemWidth(width);
 		if(Dialog::Combo("Swing", m_driveNames, m_driveIndex))
 			m_channel->SetDriveStrength(m_driveValues[m_driveIndex]);
+		HelpMarker("Peak-to-peak swing of the output (with no emphasis)");
 
 		if(ImGui::SliderFloat("Pre-cursor", &m_precursor, 0.0, 1.0, "%.2f", ImGuiSliderFlags_AlwaysClamp))
 			m_channel->SetPreCursor(m_precursor);
+		HelpMarker("Pre-cursor FFE tap value");
 
 		if(ImGui::SliderFloat("Post-cursor", &m_postcursor, 0.0, 1.0, "%.2f", ImGuiSliderFlags_AlwaysClamp))
 			m_channel->SetPostCursor(m_postcursor);
+		HelpMarker("Post-cursor FFE tap value");
 
 	}