diff --git a/core/events.go b/core/events.go
index 3a50bb03b6..4944e8ac08 100644
--- a/core/events.go
+++ b/core/events.go
@@ -27,7 +27,7 @@ func (wb *WidgetBase) EventMgr() *EventMgr {
 
 // SystemEventMgr returns the lower-level system event
 // manager for this [Widget]'s [Scene].
-func (wb *WidgetBase) SystemEventMgr() *events.Mgr {
+func (wb *WidgetBase) SystemEventMgr() *events.Source {
 	return wb.Scene.RenderWindow().SystemWindow.EventMgr()
 }
 
diff --git a/core/mainstage.go b/core/mainstage.go
index ab336f1246..2d01839a14 100644
--- a/core/mainstage.go
+++ b/core/mainstage.go
@@ -341,7 +341,7 @@ func (st *Stage) MainHandleEvent(e events.Event) {
 		return
 	}
 	st.Popups.PopupHandleEvent(e)
-	if e.IsHandled() || st.Popups.TopIsModal() {
+	if e.IsHandled() || (st.Popups != nil && st.Popups.TopIsModal()) {
 		if DebugSettings.EventTrace && e.Type() != events.MouseMove {
 			fmt.Println("Event handled by popup:", e)
 		}
diff --git a/events/mgr.go b/events/source.go
similarity index 55%
rename from events/mgr.go
rename to events/source.go
index ab0bef8e09..80f53f96a4 100644
--- a/events/mgr.go
+++ b/events/source.go
@@ -14,15 +14,16 @@ import (
 	"cogentcore.org/core/mimedata"
 )
 
-// TraceWindowPaint prints out a . for each WindowPaint event
-// - for other window events, * for mouse move events.
+// TraceWindowPaint prints out a . for each WindowPaint event,
+// - for other window events, and * for mouse move events.
 // Makes it easier to see what is going on in the overall flow.
 var TraceWindowPaint = false
 
-// Mgr manages the event construction and sending process,
-// for its parent window.  Caches state as needed
-// to generate derived events such as MouseDrag.
-type Mgr struct {
+// Source is a source of events that manages the event
+// construction and sending process for its parent window.
+// It caches state as needed to generate derived events such
+// as [MouseDrag].
+type Source struct {
 	// Deque is the event queue
 	Deque Deque
 
@@ -30,15 +31,15 @@ type Mgr struct {
 	ResettingPos bool
 
 	// Last has the prior state for key variables
-	Last MgrState
+	Last SourceState
 
 	// PaintCount is used for printing paint events as .
 	PaintCount int
 }
 
-// MgrState tracks basic event state over time
+// SourceState tracks basic event state over time
 // to enable recognition and full data for generating events.
-type MgrState struct {
+type SourceState struct {
 	// last mouse button event type (down or up)
 	MouseButtonType Types
 
@@ -64,16 +65,13 @@ type MgrState struct {
 	Key key.Codes
 }
 
-///////////////////////////////////////////////////////////////
-//  New Events
-
 // SendKey processes a basic key event and sends it
-func (em *Mgr) Key(typ Types, rn rune, code key.Codes, mods key.Modifiers) {
+func (es *Source) Key(typ Types, rn rune, code key.Codes, mods key.Modifiers) {
 	ev := NewKey(typ, rn, code, mods)
-	em.Last.Mods = mods
-	em.Last.Key = code
+	es.Last.Mods = mods
+	es.Last.Key = code
 	ev.Init()
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 
 	_, mapped := key.CodeRuneMap[code]
 
@@ -81,93 +79,93 @@ func (em *Mgr) Key(typ Types, rn rune, code key.Codes, mods key.Modifiers) {
 		(ev.HasAnyModifier(key.Control, key.Meta) || !mapped || ev.Code == key.CodeTab) {
 		che := NewKey(KeyChord, rn, code, mods)
 		che.Init()
-		em.Deque.Send(che)
+		es.Deque.Send(che)
 	}
 }
 
 // KeyChord processes a basic KeyChord event and sends it
-func (em *Mgr) KeyChord(rn rune, code key.Codes, mods key.Modifiers) {
+func (es *Source) KeyChord(rn rune, code key.Codes, mods key.Modifiers) {
 	ev := NewKey(KeyChord, rn, code, mods)
 	// no further processing of these
 	ev.Init()
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 }
 
 // MouseButton creates and sends a mouse button event with given values
-func (em *Mgr) MouseButton(typ Types, but Buttons, where image.Point, mods key.Modifiers) {
+func (es *Source) MouseButton(typ Types, but Buttons, where image.Point, mods key.Modifiers) {
 	ev := NewMouse(typ, but, where, mods)
-	em.Last.Mods = mods
-	em.Last.MouseButtonType = typ
-	em.Last.MouseButton = but
-	em.Last.MousePos = where
+	es.Last.Mods = mods
+	es.Last.MouseButtonType = typ
+	es.Last.MouseButton = but
+	es.Last.MousePos = where
 	ev.Init()
 	if typ == MouseDown {
-		em.Last.MouseDownPos = where
-		em.Last.MouseDownTime = ev.GenTime
-		em.Last.MouseMoveTime = ev.GenTime
+		es.Last.MouseDownPos = where
+		es.Last.MouseDownTime = ev.GenTime
+		es.Last.MouseMoveTime = ev.GenTime
 	}
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 }
 
 // MouseMove creates and sends a mouse move or drag event with given values
-func (em *Mgr) MouseMove(where image.Point) {
-	lastPos := em.Last.MousePos
+func (es *Source) MouseMove(where image.Point) {
+	lastPos := es.Last.MousePos
 	var ev *Mouse
-	if em.Last.MouseButtonType == MouseDown {
-		ev = NewMouseDrag(em.Last.MouseButton, where, lastPos, em.Last.MouseDownPos, em.Last.Mods)
-		ev.StTime = em.Last.MouseDownTime
-		ev.PrvTime = em.Last.MouseMoveTime
+	if es.Last.MouseButtonType == MouseDown {
+		ev = NewMouseDrag(es.Last.MouseButton, where, lastPos, es.Last.MouseDownPos, es.Last.Mods)
+		ev.StTime = es.Last.MouseDownTime
+		ev.PrvTime = es.Last.MouseMoveTime
 	} else {
-		ev = NewMouseMove(em.Last.MouseButton, where, lastPos, em.Last.Mods)
-		ev.PrvTime = em.Last.MouseMoveTime
+		ev = NewMouseMove(es.Last.MouseButton, where, lastPos, es.Last.Mods)
+		ev.PrvTime = es.Last.MouseMoveTime
 	}
 	ev.Init()
-	em.Last.MouseMoveTime = ev.GenTime
+	es.Last.MouseMoveTime = ev.GenTime
 	// if em.Win.IsCursorEnabled() {
-	em.Last.MousePos = where
+	es.Last.MousePos = where
 	// }
 	if TraceWindowPaint {
 		fmt.Printf("*")
 	}
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 }
 
 // Scroll creates and sends a scroll event with given values
-func (em *Mgr) Scroll(where image.Point, delta math32.Vector2) {
-	ev := NewScroll(where, delta, em.Last.Mods)
+func (es *Source) Scroll(where image.Point, delta math32.Vector2) {
+	ev := NewScroll(where, delta, es.Last.Mods)
 	ev.Init()
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 }
 
 // DropExternal creates and sends a Drop event with given values
-func (em *Mgr) DropExternal(where image.Point, md mimedata.Mimes) {
-	ev := NewExternalDrop(Drop, em.Last.MouseButton, where, em.Last.Mods, md)
-	em.Last.MousePos = where
+func (es *Source) DropExternal(where image.Point, md mimedata.Mimes) {
+	ev := NewExternalDrop(Drop, es.Last.MouseButton, where, es.Last.Mods, md)
+	es.Last.MousePos = where
 	ev.Init()
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 }
 
 // Touch creates and sends a touch event with the given values.
 // It also creates and sends a corresponding mouse event.
-func (em *Mgr) Touch(typ Types, seq Sequence, where image.Point) {
+func (es *Source) Touch(typ Types, seq Sequence, where image.Point) {
 	ev := NewTouch(typ, seq, where)
 	ev.Init()
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 
 	if typ == TouchStart {
-		em.MouseButton(MouseDown, Left, where, 0) // TODO: modifiers
+		es.MouseButton(MouseDown, Left, where, 0) // TODO: modifiers
 	} else if typ == TouchEnd {
-		em.MouseButton(MouseUp, Left, where, 0) // TODO: modifiers
+		es.MouseButton(MouseUp, Left, where, 0) // TODO: modifiers
 	} else {
-		em.MouseMove(where)
+		es.MouseMove(where)
 	}
 }
 
 // Magnify creates and sends a [TouchMagnify] event with the given values.
-func (em *Mgr) Magnify(scaleFactor float32, where image.Point) {
+func (es *Source) Magnify(scaleFactor float32, where image.Point) {
 	ev := NewMagnify(scaleFactor, where)
 	ev.Init()
-	em.Deque.Send(ev)
+	es.Deque.Send(ev)
 }
 
 //	func (em *Mgr) DND(act dnd.Actions, where image.Point, data mimedata.Mimes) {
@@ -177,42 +175,42 @@ func (em *Mgr) Magnify(scaleFactor float32, where image.Point) {
 //		em.Deque.Send(ev)
 //	}
 
-func (em *Mgr) Window(act WinActions) {
+func (es *Source) Window(act WinActions) {
 	ev := NewWindow(act)
 	ev.Init()
 	if TraceWindowPaint {
 		fmt.Printf("-")
 	}
-	em.Deque.SendFirst(ev)
+	es.Deque.SendFirst(ev)
 }
 
-func (em *Mgr) WindowPaint() {
+func (es *Source) WindowPaint() {
 	ev := NewWindowPaint()
 	ev.Init()
 	if TraceWindowPaint {
 		fmt.Printf(".")
-		em.PaintCount++
-		if em.PaintCount > 60 {
+		es.PaintCount++
+		if es.PaintCount > 60 {
 			fmt.Println("")
-			em.PaintCount = 0
+			es.PaintCount = 0
 		}
 	}
-	em.Deque.SendFirst(ev) // separate channel for window!
+	es.Deque.SendFirst(ev) // separate channel for window!
 }
 
-func (em *Mgr) WindowResize() {
+func (es *Source) WindowResize() {
 	ev := NewWindowResize()
 	ev.Init()
 	if TraceWindowPaint {
 		fmt.Printf("r")
 	}
-	em.Deque.SendFirst(ev)
+	es.Deque.SendFirst(ev)
 }
 
-func (em *Mgr) Custom(data any) {
+func (es *Source) Custom(data any) {
 	ce := &CustomEvent{}
 	ce.Typ = Custom
 	ce.Data = data
 	ce.Init()
-	em.Deque.Send(ce)
+	es.Deque.Send(ce)
 }
diff --git a/system/driver/base/app_single.go b/system/driver/base/app_single.go
index 036c2740a9..38b7cf254c 100644
--- a/system/driver/base/app_single.go
+++ b/system/driver/base/app_single.go
@@ -27,7 +27,7 @@ type AppSingle[D system.Drawer, W system.Window] struct {
 	App
 
 	// EvMgr is the event manager for the app
-	EvMgr events.Mgr `label:"Event manger"`
+	EvMgr events.Source `label:"Event manger"`
 
 	// Draw is the single [system.Drawer] used for the app.
 	Draw D
@@ -48,7 +48,7 @@ type AppSingler interface {
 	system.App
 
 	// EventMgr returns the single [events.Mgr] associated with this app.
-	EventMgr() *events.Mgr
+	EventMgr() *events.Source
 
 	// Drawer returns the single [system.Drawer] associated with this app.
 	Drawer() system.Drawer
@@ -66,7 +66,7 @@ func NewAppSingle[D system.Drawer, W system.Window]() AppSingle[D, W] {
 	}
 }
 
-func (a *AppSingle[D, W]) EventMgr() *events.Mgr {
+func (a *AppSingle[D, W]) EventMgr() *events.Source {
 	return &a.EvMgr
 }
 
diff --git a/system/driver/base/window_multi.go b/system/driver/base/window_multi.go
index b38dce0275..a4e38f6f73 100644
--- a/system/driver/base/window_multi.go
+++ b/system/driver/base/window_multi.go
@@ -25,7 +25,7 @@ type WindowMulti[A system.App, D system.Drawer] struct {
 	Window[A]
 
 	// EvMgr is the event manager for the window
-	EvMgr events.Mgr `label:"Event manger"`
+	EvMgr events.Source `label:"Event manger"`
 
 	// Draw is the [system.Drawer] used for this window.
 	Draw D `label:"Drawer"`
@@ -63,7 +63,7 @@ func NewWindowMulti[A system.App, D system.Drawer](a A, opts *system.NewWindowOp
 	}
 }
 
-func (w *WindowMulti[A, D]) EventMgr() *events.Mgr {
+func (w *WindowMulti[A, D]) EventMgr() *events.Source {
 	return &w.EvMgr
 }
 
diff --git a/system/driver/base/window_single.go b/system/driver/base/window_single.go
index 247d1e264a..211097b059 100644
--- a/system/driver/base/window_single.go
+++ b/system/driver/base/window_single.go
@@ -32,7 +32,7 @@ func NewWindowSingle[A AppSingler](a A, opts *system.NewWindowOptions) WindowSin
 	}
 }
 
-func (w *WindowSingle[A]) EventMgr() *events.Mgr {
+func (w *WindowSingle[A]) EventMgr() *events.Source {
 	return w.App.EventMgr()
 }
 
diff --git a/system/window.go b/system/window.go
index 75469e5908..fe133e4023 100644
--- a/system/window.go
+++ b/system/window.go
@@ -225,7 +225,7 @@ type Window interface {
 
 	// EventMgr returns the events.Mgr for this window,
 	// which manages all of the Event sending.
-	EventMgr() *events.Mgr
+	EventMgr() *events.Source
 }
 
 ////////////////////////////////////////////////////////////////////////////