diff --git a/dsf/org.eclipse.cdt.dsf.ui/src/org/eclipse/cdt/dsf/debug/internal/ui/disassembly/DisassemblyPart.java b/dsf/org.eclipse.cdt.dsf.ui/src/org/eclipse/cdt/dsf/debug/internal/ui/disassembly/DisassemblyPart.java
index 82709f52664..4ec87ca3b18 100644
--- a/dsf/org.eclipse.cdt.dsf.ui/src/org/eclipse/cdt/dsf/debug/internal/ui/disassembly/DisassemblyPart.java
+++ b/dsf/org.eclipse.cdt.dsf.ui/src/org/eclipse/cdt/dsf/debug/internal/ui/disassembly/DisassemblyPart.java
@@ -1901,6 +1901,8 @@ public abstract class DisassemblyPart extends WorkbenchPart implements IDisassem
 	private BigInteger getTopAddress() {
 		BigInteger topAddress = getAddressOfLine(fViewer.getTopIndex());
 		if (topAddress.equals(fStartAddress)) {
+			// in rare cases, the top line can be '...'
+			// don't use it as reference, take the next line
 			topAddress = getAddressOfLine(fViewer.getTopIndex() + 1);
 		}
 		return topAddress;