diff --git a/rtgui/filebrowser.cc b/rtgui/filebrowser.cc
index c3d64eb78..10d4809ed 100644
--- a/rtgui/filebrowser.cc
+++ b/rtgui/filebrowser.cc
@@ -604,13 +604,13 @@ void FileBrowser::addEntry_ (FileBrowserEntry* entry)
             std::lower_bound(
                 fd.begin(),
                 fd.end(),
-                (ThumbBrowserEntryBase*)entry,
-                [](ThumbBrowserEntryBase* a, ThumbBrowserEntryBase* b)
+                entry,
+                [](const ThumbBrowserEntryBase* a, const ThumbBrowserEntryBase* b)
                 {
-                    return *b < *a;
+                    return *a < *b;
                 }
             ),
-            (ThumbBrowserEntryBase*)entry
+            entry
         );
 
         initEntry (entry);
diff --git a/rtgui/thumbbrowserentrybase.h b/rtgui/thumbbrowserentrybase.h
index 561d652dd..55d7179ab 100644
--- a/rtgui/thumbbrowserentrybase.h
+++ b/rtgui/thumbbrowserentrybase.h
@@ -167,9 +167,9 @@ public:
     void setPosition        (int x, int y, int w, int h);
     void setOffset (int x, int y);
 
-    bool operator< (ThumbBrowserEntryBase& other)
+    bool operator <(const ThumbBrowserEntryBase& other) const
     {
-        return shortname.casefold() > other.shortname.casefold();
+        return shortname.casefold() < other.shortname.casefold();
     }
 
     ThumbBrowserEntryBase* getOriginal () const;