diff --git a/src/NewTools-Core-Tests/StPharoApplicationTest.class.st b/src/NewTools-Core-Tests/StPharoApplicationTest.class.st
index 30932d83..f870fbbc 100644
--- a/src/NewTools-Core-Tests/StPharoApplicationTest.class.st
+++ b/src/NewTools-Core-Tests/StPharoApplicationTest.class.st
@@ -9,6 +9,27 @@ Class {
 	#tag : 'Application'
 }
 
+{ #category : 'tests' }
+StPharoApplicationTest >> testSettingChangesSubscription [
+
+	| app presenter window oldSetting |
+	app := StPharoApplication basicNew.
+	app subscribeToSettingsAnnouncements.
+	presenter := StTestSettingChangeReactivePresenter new.
+	presenter application: app.
+	window := SpWindowPresenter presenter: presenter.
+	app registerWindow: window.
+
+	self assert: presenter changedSetting isNil.
+
+	oldSetting := StPharoSettings codeShowLineNumbers.
+	StPharoSettings codeShowLineNumbers: oldSetting.
+
+	self
+		assert: presenter changedSetting class
+		identicalTo: CodeShowLineNumbersChanged
+]
+
 { #category : 'tests' }
 StPharoApplicationTest >> testToolRegistration [
 	
diff --git a/src/NewTools-Core-Tests/StTestSettingChangeReactivePresenter.class.st b/src/NewTools-Core-Tests/StTestSettingChangeReactivePresenter.class.st
new file mode 100644
index 00000000..a987987b
--- /dev/null
+++ b/src/NewTools-Core-Tests/StTestSettingChangeReactivePresenter.class.st
@@ -0,0 +1,40 @@
+"
+I'm a test presenter for testing how the StPresenters react to settings changes announcements from their applications.
+"
+Class {
+	#name : 'StTestSettingChangeReactivePresenter',
+	#superclass : 'StPresenter',
+	#instVars : [
+		'changedSetting'
+	],
+	#category : 'NewTools-Core-Tests-Application',
+	#package : 'NewTools-Core-Tests',
+	#tag : 'Application'
+}
+
+{ #category : 'accessing' }
+StTestSettingChangeReactivePresenter >> changedSetting [
+
+	^ changedSetting
+]
+
+{ #category : 'layout' }
+StTestSettingChangeReactivePresenter >> defaultLayout [
+	^SpBoxLayout new
+]
+
+{ #category : 'initialization' }
+StTestSettingChangeReactivePresenter >> initialize [
+
+	super initialize.
+	self announcer
+		when: CodeShowLineNumbersChanged
+		send: #settingChanged:
+		to: self
+]
+
+{ #category : 'as yet unclassified' }
+StTestSettingChangeReactivePresenter >> settingChanged: aSettingChangedAnnouncement [
+
+	changedSetting := aSettingChangedAnnouncement
+]
diff --git a/src/NewTools-Core/StPharoApplication.class.st b/src/NewTools-Core/StPharoApplication.class.st
index c1b182d6..c2210b36 100644
--- a/src/NewTools-Core/StPharoApplication.class.st
+++ b/src/NewTools-Core/StPharoApplication.class.st
@@ -47,6 +47,12 @@ StPharoApplication class >> use: application during: aBlock [
 	^ aBlock ensure: [ Current := oldCurrent ]
 ]
 
+{ #category : 'settings' }
+StPharoApplication >> codeShowLineNumbers [
+
+	^ StPharoSettings codeShowLineNumbers
+]
+
 { #category : 'accessing - resources' }
 StPharoApplication >> defaultWindowExtent [
 	
@@ -64,14 +70,18 @@ StPharoApplication >> defaultWindowPresenterClass [
 StPharoApplication >> initialize [
 
 	super initialize.
-	self initializeConfiguration
+	self initializeConfiguration.
+	self subscribeToSettingsAnnouncements
 ]
 
 { #category : 'initialization' }
 StPharoApplication >> initializeConfiguration [
 
 	self resetConfiguration.
-	self class codeSupportAnnouncer weak when: UIThemeChanged send: #resetConfiguration to: self
+	self class codeSupportAnnouncer weak
+		when: UIThemeChanged
+		send: #resetConfiguration
+		to: self
 ]
 
 { #category : 'private - factory' }
@@ -115,6 +125,13 @@ StPharoApplication >> run [
 StPharoApplication >> shutDown: quitting [
 ]
 
+{ #category : 'settings' }
+StPharoApplication >> stPharoSettingChanged: aPharoSettingChangeAnnouncement [
+
+	(self windows collect: #presenter) do: [ :presenter |
+		presenter announce: aPharoSettingChangeAnnouncement ]
+]
+
 { #category : 'system startup' }
 StPharoApplication >> startUp: resuming [
 
@@ -122,6 +139,15 @@ StPharoApplication >> startUp: resuming [
 	self resetBackend.
 ]
 
+{ #category : 'settings' }
+StPharoApplication >> subscribeToSettingsAnnouncements [
+
+	self class codeSupportAnnouncer weak
+		when: CodeShowLineNumbersChanged
+		send: #stPharoSettingChanged:
+		to: self
+]
+
 { #category : 'tool management' }
 StPharoApplication >> toolNamed: aName [
 
diff --git a/src/NewTools-Core/StPharoSettings.class.st b/src/NewTools-Core/StPharoSettings.class.st
index e708d5fa..adea4c12 100644
--- a/src/NewTools-Core/StPharoSettings.class.st
+++ b/src/NewTools-Core/StPharoSettings.class.st
@@ -14,19 +14,15 @@ Class {
 StPharoSettings class >> codeShowLineNumbers [
 	"Defines if code editors will display line numbers"
 
-	^ CodeShowLineNumbers ifNil: [ CodeShowLineNumbers := self defaultCodeShowLineNumbers ]
+	^ CodeShowLineNumbers ifNil: [
+		  CodeShowLineNumbers := StPharoApplication defaultCodeShowLineNumbers ]
 ]
 
 { #category : 'settings' }
-StPharoSettings class >> codeShowLineNumbers: aBoolean [ 
+StPharoSettings class >> codeShowLineNumbers: aBoolean [
 
-	CodeShowLineNumbers := aBoolean
-]
-
-{ #category : 'defaults' }
-StPharoSettings class >> defaultCodeShowLineNumbers [
-
-	^ true
+	CodeShowLineNumbers := aBoolean.
+	self codeSupportAnnouncer announce: CodeShowLineNumbersChanged new
 ]
 
 { #category : 'defaults' }
diff --git a/src/NewTools-Debugger/StDebugger.class.st b/src/NewTools-Debugger/StDebugger.class.st
index 521102d7..40ecf658 100644
--- a/src/NewTools-Debugger/StDebugger.class.st
+++ b/src/NewTools-Debugger/StDebugger.class.st
@@ -531,6 +531,12 @@ StDebugger >> codeLayout [
 		  yourself
 ]
 
+{ #category : 'subscription' }
+StDebugger >> codeShowLineNumbersChanged: aCodeShowLineNumbersChangedAnnouncement [
+
+	self code announce: aCodeShowLineNumbersChangedAnnouncement
+]
+
 { #category : 'initialization' }
 StDebugger >> connectPresenters [
 
@@ -797,10 +803,11 @@ StDebugger >> initialize [
 	super initialize.
 	self debuggerActionModel updateContextPredicate.
 	self forceSessionUpdate.
-  	self subscribeToExtensionToggleAnnouncement.
+	self subscribeToExtensionToggleAnnouncement.
 	self subscribeToLayoutChangesAnnouncement.
-	
-	programmaticallyClosed := false.
+	self subscribeToSettingsChangesAnnouncements.
+
+	programmaticallyClosed := false
 ]
 
 { #category : 'initialization' }
@@ -815,7 +822,7 @@ StDebugger >> initializeCode [
 
 	code := self instantiate: StDebuggerCodePresenter.
 	code debuggerActionModel: self debuggerActionModel.
-	code whenSubmitDo: [ :text | 
+	code whenSubmitDo: [ :text |
 		self acceptCodeChanges: text string forContext: self selectedContext ].
 	code whenResetDo: [ self discardCodeChangesFor: self selectedContext ]
 ]
@@ -857,7 +864,6 @@ StDebugger >> initializePresenters [
 	self initializeInspector.
 	self initializeExtensionTools.
 	self setStackAndCodeContainer.
-
 	self layout: self defaultLayout
 ]
 
@@ -1200,6 +1206,12 @@ StDebugger >> settings [
 	^ self class settings 
 ]
 
+{ #category : 'subscription' }
+StDebugger >> showLineNumbersAndUpdate [
+
+	self code showLineNumbersAndUpdate
+]
+
 { #category : 'stack' }
 StDebugger >> stack [
 	^ self debuggerActionModel stack 
@@ -1374,6 +1386,15 @@ StDebugger >> subscribeToLayoutChangesAnnouncement [
 	self class codeSupportAnnouncer weak when: StDebuggerLayoutChangedAnnouncement send: #updateLayout to: self
 ]
 
+{ #category : 'subscription' }
+StDebugger >> subscribeToSettingsChangesAnnouncements [
+
+	self announcer
+		when: CodeShowLineNumbersChanged
+		send: #codeShowLineNumbersChanged:
+		to: self
+]
+
 { #category : 'toolbar' }
 StDebugger >> toolbarAdvancedCommandsGroups [