diff -up evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-dom-functions.c.composer-font-color evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-dom-functions.c
--- evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-dom-functions.c.composer-font-color	2017-03-24 13:43:34.992659166 +0100
+++ evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-dom-functions.c	2017-03-24 13:43:34.997659165 +0100
@@ -2834,6 +2834,8 @@ body_keypress_event_cb (WebKitDOMElement
 
 	g_return_if_fail (E_IS_EDITOR_PAGE (editor_page));
 
+	e_editor_page_set_is_processing_keypress_event (editor_page, TRUE);
+
 	document = webkit_dom_node_get_owner_document (WEBKIT_DOM_NODE (element));
 	dom_window = webkit_dom_document_get_default_view (document);
 	dom_selection = webkit_dom_dom_window_get_selection (dom_window);
@@ -3583,7 +3585,13 @@ body_input_event_cb (WebKitDOMElement *e
 {
 	g_return_if_fail (E_IS_EDITOR_PAGE (editor_page));
 
-	e_editor_dom_body_input_event_process (editor_page, event);
+	/* Only process the input event if it was triggered by the key press
+	 * and not i.e. by exexCommand. This behavior changed when the support
+	 * for beforeinput event was introduced in WebKit. */
+	if (e_editor_page_is_processing_keypress_event (editor_page))
+		e_editor_dom_body_input_event_process (editor_page, event);
+
+	e_editor_page_set_is_processing_keypress_event (editor_page, FALSE);
 }
 
 void
diff -up evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.c.composer-font-color evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.c
--- evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.c.composer-font-color	2017-02-07 17:48:51.000000000 +0100
+++ evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.c	2017-03-24 13:43:34.997659165 +0100
@@ -64,6 +64,7 @@ struct _EEditorPagePrivate {
 	gboolean pasting_content_from_itself;
 	gboolean renew_history_after_coordinates;
 	gboolean allow_top_signature;
+	gboolean processing_keypress_event;
 
 	GHashTable *inline_images;
 
@@ -246,6 +247,7 @@ e_editor_page_init (EEditorPage *editor_
 	editor_page->priv->block_format = E_CONTENT_EDITOR_BLOCK_FORMAT_PARAGRAPH;
 	editor_page->priv->force_image_load = FALSE;
 	editor_page->priv->html_mode = TRUE;
+	editor_page->priv->processing_keypress_event = FALSE;
 	editor_page->priv->return_key_pressed = FALSE;
 	editor_page->priv->space_key_pressed = FALSE;
 	editor_page->priv->smiley_written = FALSE;
@@ -559,6 +561,23 @@ e_editor_page_set_alignment (EEditorPage
 }
 
 gboolean
+e_editor_page_is_processing_keypress_event (EEditorPage *editor_page)
+{
+	g_return_val_if_fail (E_IS_EDITOR_PAGE (editor_page), FALSE);
+
+	return editor_page->priv->processing_keypress_event;
+}
+
+void
+e_editor_page_set_is_processing_keypress_event (EEditorPage *editor_page,
+                                                gboolean processing_keypress_event)
+{
+	g_return_if_fail (E_IS_EDITOR_PAGE (editor_page));
+
+	editor_page->priv->processing_keypress_event = processing_keypress_event;
+}
+
+gboolean
 e_editor_page_get_return_key_pressed (EEditorPage *editor_page)
 {
 	g_return_val_if_fail (E_IS_EDITOR_PAGE (editor_page), FALSE);
diff -up evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.h.composer-font-color evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.h
--- evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.h.composer-font-color	2017-02-07 17:48:51.000000000 +0100
+++ evolution-3.22.6/modules/webkit-editor/web-extension/e-editor-page.h	2017-03-24 13:43:34.997659165 +0100
@@ -112,6 +112,11 @@ void		e_editor_page_set_alignment	(EEdit
 						 EContentEditorAlignment value);
 gint		e_editor_page_get_word_wrap_length
 						(EEditorPage *editor_page);
+gboolean	e_editor_page_is_processing_keypress_event
+						(EEditorPage *editor_page);
+void		e_editor_page_set_is_processing_keypress_event
+						(EEditorPage *editor_page,
+						 gboolean processing_keypress_event);
 gboolean	e_editor_page_get_return_key_pressed
 						(EEditorPage *editor_page);
 void		e_editor_page_set_return_key_pressed