The plugin produces errors on the 404 page:
Notice: Undefined index: in /some/path/pico/plugins/PicoPlacing/PicoPlacing.php on line 134
Notice: Undefined index: in /some/path/pico/plugins/PicoPlacing/PicoPlacing.php on line 135

Can be hotfixed by checking for $currentPage in onPagesLoaded:

if ( isset( $currentPage ) ) {
    $curr = $currentPage['placing'];
    
    $keys = array_keys($sorted_pages);
    $keyIndexes = array_flip( $keys );
    
    $prev = ( isset( $keys[ $keyIndexes[ $curr ] - 1 ] ) ) ? $prev = $keys[ $keyIndexes[ $curr ] - 1 ] : FALSE;
    $next = ( isset( $keys[ $keyIndexes[ $curr ] + 1 ] ) ) ? $next = $keys[ $keyIndexes[ $curr ] + 1 ] : FALSE;
    
    $nextPage = ( $next ) ? $sorted_pages[$next] : null;
    $previousPage = ( $prev ) ? $sorted_pages[$prev] : null;
}

Hi,

the first thing, Ive recognized is, that the plugin is not compatible with the sitemap plugin (https://github.com/mcbSolutions/Pico-Plugins/tree/master/mcb_HtmlSitemap). There are pages not shown when Pico-Placing is activ.

The second thing is, that I want to suggest the plugin to work on a level basis not over all levels as it is now. That means the following setting

index.md (Home) Placing: 1
impress.md Placing: 3
verzeichnis/index.md Placing: 4
verzeichnis/test.md
anderes/index.md Placing: 2
anderes/anprobe.md Placing: 2
anderes/probe.md Placing: 3
anderes/wechsel.md Placing: 1

should lead to the following navigation / menu:

• Home
• Anderes
  -- Wechsel
  -- Anprobe
  -- Probe
• Impress
• Verzeichnis
  -- Test

Who can make this possible?

Regards,
Christian

Thanks very much for this plugin, excatly what i'm looking for :)

But if you don't specify any Placing it disapear from Pico_Edit Plugin Editor List.
My suggestion is adding an automatic Placing computation start from 9999 in onPagesLoaded function:

            $i = 1;
            foreach ($pages as $page) {
                
                $sortindex = $page['placing'];
                if (!$sortindex) $sortindex = 9999+$i;
                
                $sorted_pages[$sortindex] = $page;
                $i++;
            }

In this case, untagged "Placing" pages always comes after tagged pages, and will not be ignored by Pico_Edit.
And voila,
Thanks for your reading,
m4pleberry 8)