FIJISettingsViewer: add tooltips for FIU rename and remove buttons

bin/Tk/FIJISettingsViewer.pm

@@ -1164,11 +1164,15 @@ sub _add_fiu ($$) {
 
     # Button to rename the FIU
     my $rename_button = $fr_fiu->Button(
-
         #-text    => 'Rename',
         -image   => Tk::FIJIUtils::rename_image($self->{'mw'}),
         -command => [\&_rename_fiu_dialog, $self, $i, $fr_fiu],
     );
+    $self->{'balloon'}->attach(
+        $rename_button,
+        -balloonposition => 'mouse',
+        -msg             => "Set a name for FIU $i."
+    );
 
     # Button to delete the FIU
     my $del_button = $fr_fiu->Button(
@@ -1177,6 +1181,12 @@ sub _add_fiu ($$) {
         -image   => Tk::FIJIUtils::delete_image($self->{'mw'}),
         -command => [\&remove_fiu, $self, $i],
     );
+    $self->{'balloon'}->attach(
+        $del_button,
+        -balloonposition => 'mouse',
+        -msg             => "Remove FIU $i."
+    );
+
     $model_menu->configure(
         '-command' => sub {
             my $logger = get_logger("");