Four menu options from Edit menu crashes Pinta

[grofaty]

Pinta from master on Windows XP.
1. Close down all images.
2. Now select one of the following:
a) Edit | Deselect All
b) Edit | Delete Selection
c) Edit | Fill Selection
d) Edit | Invert Selection

All above four options crashes Pinta with the same error:
============
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.InvalidOperationException: Tried to get WorkspaceManager.ActiveDocument when there are no open Documents. Check HasOpenDocuments first.
   at Pinta.Core.WorkspaceManager.get_ActiveDocument() in c:\aaa\Pinta-master\Pinta.Core\Managers\WorkspaceManager.cs:line 57
   at Pinta.Core.EditActions.HandlePintaCoreActionsEditDeselectActivated(Object sender, EventArgs e) in c:\aaa\Pinta-master\Pinta.Core\Actions\EditActions.cs:line 223
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
   at System.RuntimeMethodHandle.InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Delegate.DynamicInvokeImpl(Object[] args)
   at GLib.Signal.ClosureInvokedCB(Object o, ClosureInvokedArgs args)
   at GLib.SignalClosure.Invoke(ClosureInvokedArgs args)
   at GLib.SignalClosure.MarshalCallback(IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data)
============

I know selection this options is stupid if there is no canvas, but in my humble opinion we should have zero tolerance to crashes.

I suggest to make all above four options grayed out if there is no image opened in Pinta.

[grofaty (grofaty)]

The same crash appears:
1. Close down all images.
2. Click on Deselect All button from toolbar and crash with the same error appears.

[Cameron White (cameronwhite91)]

Fixed: https://github.com/PintaProject/Pinta/commit/5a25b127858f6bf96ed22566d30c7449ece011d7

[grofaty (grofaty)]

Tested using latest master on Windows XP. This four menus options and button on toolbar is grayed out when no canvas exists, so the problem is fixed. Thanks.