Geany - Grab focus after opening each document (Scintilla Widgets).

gistfile1.txt

diff --git a/src/keyfile.c b/src/keyfile.c
index ad6aea5..5577b39 100644
--- a/src/keyfile.c
+++ b/src/keyfile.c
@@ -1031,6 +1031,7 @@ static gboolean open_session_file(gchar **tmp, guint len)
 			editor_set_line_wrapping(doc->editor, line_wrapping);
 			doc->editor->line_breaking = line_breaking;
 			doc->editor->auto_indent = auto_indent;
+			gtk_widget_grab_focus(doc->editor->sci);
 			ret = TRUE;
 		}
 	}

Or this could be done once for each time project files are opened, maybe in project.c around line 314.