I had similar issue under Ubuntu 20.04.6 LTS opening and pasting second new image.
Also had other Pinta crashes thats made me use GNU which is too much for my use.
I didn't have any crashes while running Ubuntu 18 that I can remember or at least not the frequency since I upgraded to Ubuntu 20.04 and Pinta 1.7.1.
So I finally was going to open a bug report but found this 2016 similar bug.
Do you need me to open a new bug report and what doc needs to be gathered?
Unhandled Execption:
Exception has been thrown by the target of an invocation.
Details
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object
at Pinta.Gui.Widgets.CanvasRenderer.get_OffsetLayer () [0x00042] in <4b6bf512a4f54b1caeb747238f48b70c>:0
at Pinta.Gui.Widgets.CanvasRenderer.CreateOffsetLayer (Pinta.Core.Layer original) [0x00001] in <4b6bf512a4f54b1caeb747238f48b70c>:0
at Pinta.Gui.Widgets.CanvasRenderer.Render (System.Collections.Generic.List`1[T] layers, Cairo.ImageSurface dst, Gdk.Point offset) [0x000af] in <4b6bf512a4f54b1caeb747238f48b70c>:0
at Pinta.Gui.Widgets.LayersListWidget.Reset () [0x000d2] in <4b6bf512a4f54b1caeb747238f48b70c>:0
at Pinta.Gui.Widgets.LayersListWidget.HandleHistoryItemAdded (System.Object sender, System.EventArgs e) [0x00001] in <4b6bf512a4f54b1caeb747238f48b70c>:0
at (wrapper delegate-invoke) System.EventHandler`1[Pinta.Core.HistoryItemAddedEventArgs].invoke_void_object_TEventArgs(object,Pinta.Core.HistoryItemAddedEventArgs)
at Pinta.Core.HistoryManager.OnHistoryItemAdded (Pinta.Core.BaseHistoryItem item) [0x00019] in <a4889b1da6f14fd68fb8fe10729e7f1d>:0
at Pinta.Core.DocumentWorkspaceHistory.PushNewItem (Pinta.Core.BaseHistoryItem newItem) [0x00117] in <a4889b1da6f14fd68fb8fe10729e7f1d>:0
at Pinta.Core.HistoryManager.PushNewItem (Pinta.Core.BaseHistoryItem newItem) [0x00010] in <a4889b1da6f14fd68fb8fe10729e7f1d>:0
at Pinta.Tools.MoveSelectedTool.OnFinishTransform (Cairo.Matrix transform) [0x00049] in <6b2549ee3b5d45fd8a1e7fd000a086f4>:0
at Pinta.Tools.BaseTransformTool.OnMouseUp (Gtk.DrawingArea canvas, Gtk.ButtonReleaseEventArgs args, Cairo.PointD point) [0x0001c] in <6b2549ee3b5d45fd8a1e7fd000a086f4>:0
at Pinta.Core.BaseTool.DoMouseUp (Gtk.DrawingArea canvas, Gtk.ButtonReleaseEventArgs args, Cairo.PointD point) [0x00030] in <a4889b1da6f14fd68fb8fe10729e7f1d>:0
at Pinta.Gui.Widgets.PintaCanvas+<PintaCanvas>c__AnonStorey0.<>m__3 (System.Object sender, Gtk.ButtonReleaseEventArgs e) [0x00038] in <4b6bf512a4f54b1caeb747238f48b70c>:0
at (wrapper managed-to-native) System.Reflection.RuntimeMethodInfo.InternalInvoke(System.Reflection.RuntimeMethodInfo,object,object[],System.Exception&)
at System.Reflection.RuntimeMethodInfo.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x0007c] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
--- End of inner exception stack trace ---
at System.Reflection.RuntimeMethodInfo.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x0009a] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Delegate.DynamicInvokeImpl (System.Object[] args) [0x0010d] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.MulticastDelegate.DynamicInvokeImpl (System.Object[] args) [0x0000b] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Delegate.DynamicInvoke (System.Object[] args) [0x00000] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at GLib.Signal.ClosureInvokedCB (System.Object o, GLib.ClosureInvokedArgs args) [0x0006d] in <918680a31aa84cb89cfa7cab56ea29b8>:0
at GLib.SignalClosure.Invoke (GLib.ClosureInvokedArgs args) [0x0000c] in <918680a31aa84cb89cfa7cab56ea29b8>:0
at GLib.SignalClosure.MarshalCallback (System.IntPtr raw_closure, System.IntPtr return_val, System.UInt32 n_param_vals, System.IntPtr param_values, System.IntPtr invocation_hint, System.IntPtr marshal_data) [0x0012f] in <918680a31aa84cb89cfa7cab56ea29b8>:0
I had similar issue under Ubuntu 20.04.6 LTS opening and pasting second new image.
Also had other Pinta crashes thats made me use GNU which is too much for my use.
I didn't have any crashes while running Ubuntu 18 that I can remember or at least not the frequency since I upgraded to Ubuntu 20.04 and Pinta 1.7.1.
So I finally was going to open a bug report but found this 2016 similar bug.
Do you need me to open a new bug report and what doc needs to be gathered?
Unhandled Execption:
Exception has been thrown by the target of an invocation.
Details Reflection. TargetInvocatio nException: Exception has been thrown by the target of an invocation. ---> System. NullReferenceEx ception: Object reference not set to an instance of an object Widgets. CanvasRenderer. get_OffsetLayer () [0x00042] in <4b6bf512a4f54b 1caeb747238f48b 70c>:0 Widgets. CanvasRenderer. CreateOffsetLay er (Pinta.Core.Layer original) [0x00001] in <4b6bf512a4f54b 1caeb747238f48b 70c>:0 Widgets. CanvasRenderer. Render (System. Collections. Generic. List`1[ T] layers, Cairo.ImageSurface dst, Gdk.Point offset) [0x000af] in <4b6bf512a4f54b 1caeb747238f48b 70c>:0 Widgets. LayersListWidge t.Reset () [0x000d2] in <4b6bf512a4f54b 1caeb747238f48b 70c>:0 Widgets. LayersListWidge t.HandleHistory ItemAdded (System.Object sender, System.EventArgs e) [0x00001] in <4b6bf512a4f54b 1caeb747238f48b 70c>:0 EventHandler` 1[Pinta. Core.HistoryIte mAddedEventArgs ].invoke_ void_object_ TEventArgs( object, Pinta.Core. HistoryItemAdde dEventArgs) HistoryManager. OnHistoryItemAd ded (Pinta. Core.BaseHistor yItem item) [0x00019] in <a4889b1da6f14f d68fb8fe10729e7 f1d>:0 DocumentWorkspa ceHistory. PushNewItem (Pinta. Core.BaseHistor yItem newItem) [0x00117] in <a4889b1da6f14f d68fb8fe10729e7 f1d>:0 HistoryManager. PushNewItem (Pinta. Core.BaseHistor yItem newItem) [0x00010] in <a4889b1da6f14f d68fb8fe10729e7 f1d>:0 MoveSelectedToo l.OnFinishTrans form (Cairo.Matrix transform) [0x00049] in <6b2549ee3b5d45 fd8a1e7fd000a08 6f4>:0 BaseTransformTo ol.OnMouseUp (Gtk.DrawingArea canvas, Gtk.ButtonRelea seEventArgs args, Cairo.PointD point) [0x0001c] in <6b2549ee3b5d45 fd8a1e7fd000a08 6f4>:0 BaseTool. DoMouseUp (Gtk.DrawingArea canvas, Gtk.ButtonRelea seEventArgs args, Cairo.PointD point) [0x00030] in <a4889b1da6f14f d68fb8fe10729e7 f1d>:0 Widgets. PintaCanvas+ <PintaCanvas> c__AnonStorey0. <>m__3 (System.Object sender, Gtk.ButtonRelea seEventArgs e) [0x00038] in <4b6bf512a4f54b 1caeb747238f48b 70c>:0 Reflection. RuntimeMethodIn fo.InternalInvo ke(System. Reflection. RuntimeMethodIn fo,object, object[ ],System. Exception& ) Reflection. RuntimeMethodIn fo.Invoke (System.Object obj, System. Reflection. BindingFlags invokeAttr, System. Reflection. Binder binder, System.Object[] parameters, System. Globalization. CultureInfo culture) [0x0007c] in <12b418a7818c4c a0893feeaaf67f1 e7f>:0 Reflection. RuntimeMethodIn fo.Invoke (System.Object obj, System. Reflection. BindingFlags invokeAttr, System. Reflection. Binder binder, System.Object[] parameters, System. Globalization. CultureInfo culture) [0x0009a] in <12b418a7818c4c a0893feeaaf67f1 e7f>:0 Reflection. MethodBase. Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <12b418a7818c4c a0893feeaaf67f1 e7f>:0 Delegate. DynamicInvokeIm pl (System.Object[] args) [0x0010d] in <12b418a7818c4c a0893feeaaf67f1 e7f>:0 MulticastDelega te.DynamicInvok eImpl (System.Object[] args) [0x0000b] in <12b418a7818c4c a0893feeaaf67f1 e7f>:0 Delegate. DynamicInvoke (System.Object[] args) [0x00000] in <12b418a7818c4c a0893feeaaf67f1 e7f>:0 ClosureInvokedC B (System.Object o, GLib.ClosureInv okedArgs args) [0x0006d] in <918680a31aa84c b89cfa7cab56ea2 9b8>:0 ure.Invoke (GLib.ClosureIn vokedArgs args) [0x0000c] in <918680a31aa84c b89cfa7cab56ea2 9b8>:0 ure.MarshalCall back (System.IntPtr raw_closure, System.IntPtr return_val, System.UInt32 n_param_vals, System.IntPtr param_values, System.IntPtr invocation_hint, System.IntPtr marshal_data) [0x0012f] in <918680a31aa84c b89cfa7cab56ea2 9b8>:0
System.
at Pinta.Gui.
at Pinta.Gui.
at Pinta.Gui.
at Pinta.Gui.
at Pinta.Gui.
at (wrapper delegate-invoke) System.
at Pinta.Core.
at Pinta.Core.
at Pinta.Core.
at Pinta.Tools.
at Pinta.Tools.
at Pinta.Core.
at Pinta.Gui.
at (wrapper managed-to-native) System.
at System.
--- End of inner exception stack trace ---
at System.
at System.
at System.
at System.
at System.
at GLib.Signal.
at GLib.SignalClos
at GLib.SignalClos