Allow switching to non-form view even if no record is selected

Closes #13511
(grafted from 532aa26b3fa2e4f67078bcb8a300bb6d7610e67d)

--HG--
branch : 7.0

sao/src/screen.js

@@ -926,6 +926,18 @@
         get number_of_views() {
             return this.views.length + this.view_to_load.length;
         },
+        get view_index() {
+            return this.views.indexOf(this.current_view);
+        },
+        get next_view_type() {
+            var views = this.views.concat(this.view_to_load)
+            var next_view_index = (this.view_index + 1) % views.length;
+            var next_view = views[next_view_index];
+            if (typeof next_view != 'string') {
+                next_view = next_view.view_type;
+            }
+            return next_view;
+        },
         switch_view: function(
             view_type=null, view_id=null, creatable=null, display=true) {
             if (view_id !== null) {

sao/src/tab.js

@@ -1452,6 +1452,7 @@
                 }
             }
             const view_type = this.screen.current_view.view_type;
+            var next_view_type = this.screen.next_view_type;
             const has_views = this.screen.number_of_views > 1;
             var buttons = ['print', 'relate', 'email', 'attach'];
             for (const button_id of buttons) {
@@ -1472,7 +1473,9 @@
                 set_sensitive(button_id, position && can_be_sensitive);
             }
             set_sensitive(
-                'switch_', (position || (view_type == 'form')) && has_views);
+                'switch_',
+                (position || (view_type == 'form') || (next_view_type != 'form')) &&
+                has_views);
             set_sensitive('delete_', this.screen.deletable);
             set_sensitive('previous', this.screen.has_previous());
             set_sensitive('next', this.screen.has_next());

tryton/tryton/gui/window/form.py

@@ -578,6 +578,7 @@ class Form(TabContent):
         name = str(position) if position else '_'
         selected = len(self.screen.selected_records)
         view_type = self.screen.current_view.view_type
+        next_view_type = self.screen.next_view_type
         has_views = self.screen.number_of_views > 1
         if selected > 1:
             name += '#%i' % selected
@@ -593,7 +594,9 @@ class Form(TabContent):
                     for b in self.screen.get_buttons())
             set_sensitive(button_id, bool(position) and can_be_sensitive)
         set_sensitive(
-            'switch', (position or view_type == 'form') and has_views)
+            'switch',
+            (position or view_type == 'form' or next_view_type != 'form')
+            and has_views)
         set_sensitive('remove', self.screen.deletable)
         set_sensitive('previous', self.screen.has_prev())
         set_sensitive('next', self.screen.has_next())

tryton/tryton/gui/window/view_form/screen/screen.py

@@ -536,6 +536,19 @@ class Screen:
     def number_of_views(self):
         return len(self.views) + len(self.view_to_load)
 
+    @property
+    def view_index(self):
+        return self.__current_view
+
+    @property
+    def next_view_type(self):
+        views = self.views + self.view_to_load
+        next_view_index = (self.view_index + 1) % len(views)
+        next_view = views[next_view_index]
+        if not isinstance(next_view, str):
+            next_view = next_view.view_type
+        return next_view
+
     def switch_view(
             self, view_type=None, view_id=None, creatable=None, display=True):
         if view_id is not None: