For anyone else who comes across this requirement, messages weren't printing in the Panel template because they were already being called by the page preprocess function in core.

As per this answer about a similar requirement with nodes, the thing to do is to edit your page preprocess function to include this:

function YOURTHEME_preprocess_page(&$variables) {
  // This disables message-printing on ALL page displays
  $variables['show_messages'] = FALSE;
}

And put this in your preprocess function in your layout.inc file:

function YOURTHEME_preprocess_PANEL_LAYOUT(&$variables) {
  $variables['messages'] = theme('status_messages');
}

For anyone else who comes across this requirement, messages weren't printing in the Panel template because they were already being called by the page preprocess function in core.

As per this answer about a similar requirement with nodes, the thing to do is to edit your page preprocess function to include this:

function YOURTHEME_preprocess_page(&$variables) {
  // This disables message-printing on ALL page displays
  $variables['show_messages'] = FALSE;
}

And put this in your preprocess function in your layout.inc file:

function YOURTHEME_preprocess_PANEL_LAYOUT(&$variables) {
  $variables['messages'] = theme('status_messages');
}

For anyone else who comes across this requirement, messages weren't printing in the Panel template because they were already being called by the page preprocess function in core.

As per this answer about a similar requirement with nodes, the thing to do is to edit your page preprocess function to include this:

function YOURTHEME_preprocess_page(&$variables) {
  // This disables message-printing on ALL page displays
  $variables['show_messages'] = FALSE;
}

And put this in your preprocess function in your layout.inc file

function YOURTHEME_preprocess_PANEL_LAYOUT(&$variables) {
  $variables['messages'] = theme('status_messages');
}

For anyone else who comes across this requirement, messages weren't printing in the Panel template because they were already being called by the page preprocess function in core.

As per this answer about a similar requirement with nodes, the thing to do is to edit your page preprocess function to include this:

function YOURTHEME_preprocess_page(&$variables) {
  // This disables message-printing on ALL page displays
  $variables['show_messages'] = FALSE;
}

And put this in your preprocess function in your layout.inc file:

function YOURTHEME_preprocess_PANEL_LAYOUT(&$variables) {
  $variables['messages'] = theme('status_messages');
}