diff --git a/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/CompletionProposalPopup.java b/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/CompletionProposalPopup.java
index 3333fe01085e..f1646492efd8 100644
--- a/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/CompletionProposalPopup.java
+++ b/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/CompletionProposalPopup.java
@@ -1408,7 +1408,8 @@ public boolean verifyKey(VerifyEvent e) {
 					break;
 
 				default :
-					if (e.keyCode != SWT.CAPS_LOCK && e.keyCode != SWT.MOD1 && e.keyCode != SWT.MOD2 && e.keyCode != SWT.MOD3 && e.keyCode != SWT.MOD4) {
+					// On Linux ALT_GR is the level3 switch (at least on the US-INTL layout), when using 'include "level3(YOURKEY)"' in the xkb file
+					if (e.keyCode != SWT.CAPS_LOCK && e.keyCode != SWT.MOD1 && e.keyCode != SWT.MOD2 && e.keyCode != SWT.MOD3 && e.keyCode != SWT.MOD4 && e.keyCode != SWT.ALT_GR) {
 						hide();
 					}
 					return true;
diff --git a/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java b/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java
index 5a0e972b7b63..72a08b53deea 100644
--- a/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java
+++ b/bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java
@@ -801,7 +801,8 @@ private boolean contextSelectorKeyPressed(VerifyEvent e) {
 					break;
 
 				default :
-					if (e.keyCode != SWT.CAPS_LOCK && e.keyCode != SWT.MOD1 && e.keyCode != SWT.MOD2 && e.keyCode != SWT.MOD3 && e.keyCode != SWT.MOD4) {
+					// On Linux ALT_GR is the level3 switch (at least on the US-INTL layout), when using 'include "level3(YOURKEY)"' in the xkb file
+					if (e.keyCode != SWT.CAPS_LOCK && e.keyCode != SWT.MOD1 && e.keyCode != SWT.MOD2 && e.keyCode != SWT.MOD3 && e.keyCode != SWT.MOD4 && e.keyCode != SWT.ALT_GR) {
 						hideContextSelector();
 					}
 					return true;
@@ -844,7 +845,8 @@ private boolean contextInfoPopupKeyPressed(KeyEvent e) {
 					validateContextInformation();
 					break;
 				default:
-					if (e.keyCode != SWT.CAPS_LOCK && e.keyCode != SWT.MOD1 && e.keyCode != SWT.MOD2 && e.keyCode != SWT.MOD3 && e.keyCode != SWT.MOD4) {
+					// On Linux ALT_GR is the level3 switch (at least on the US-INTL layout), when using 'include "level3(YOURKEY)"' in the xkb file
+					if (e.keyCode != SWT.CAPS_LOCK && e.keyCode != SWT.MOD1 && e.keyCode != SWT.MOD2 && e.keyCode != SWT.MOD3 && e.keyCode != SWT.MOD4 && e.keyCode != SWT.ALT_GR) {
 						hideContextInfoPopup(true);
 					}
 					break;