[shotwell] Mark scroll events as handled

[Jens Georg <jensgeorg src gnome org>]

commit 341521aca2c715fd7232dd9f7d5c6274da94b760
Author: Jens Georg <mail jensge org>
Date:   Sun Oct 28 18:43:29 2018 +0100

    Mark scroll events as handled

 src/PhotoPage.vala | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/PhotoPage.vala b/src/PhotoPage.vala
index f09ba189..537d65ca 100644
--- a/src/PhotoPage.vala
+++ b/src/PhotoPage.vala
@@ -763,7 +763,7 @@ public abstract class EditingHostPage : SinglePhotoPage {
             return false;
 
         zoom_about_event_cursor_point(event, ZOOM_INCREMENT_SIZE);
-        return false;
+        return true;
     }
     
     protected override bool on_mousewheel_down(Gdk.EventScroll event) {
@@ -771,7 +771,7 @@ public abstract class EditingHostPage : SinglePhotoPage {
             return false;
         
         zoom_about_event_cursor_point(event, -ZOOM_INCREMENT_SIZE);
-        return false;
+        return true;
     }
 
     protected override void restore_zoom_state() {