changing layer order in inkscape 0.91pre3 fails

[KaOS-bEat]

reproduce in inkscape 0.91pre3 on OSX:

- create a new layer( let's call it "new layer") and create it above another layer(let's call it "existing layer")
- change the order and move "new layer" below "existing layer"
- select an object from "existing layer" and do a "Layer => move selection to layer below" from the menu.
- nothing happens
- select object and do a "layer => move selection to layer ..." and select "new layer"
- object is moved to new layer but appears ABOVE existing layer

desired outcome:

it should be below, because I changed the order in the layers panel

[KaOS-bEat (kasper-jordaens)]

I just found out the bug only triggers when rearranging layer order with drag&drop, not when reorganising layers with the green arrow buttons

[jazzynico (jazzynico)]

Confirmed on Windows XP, Inkscape trunk revision 13851.

When I save the file and then use File>Revert, the layers list show the layers in their creation order.
Steps:
1. Create a new layer.
2. Move the layer in the Layers dialog (by drag'n'drop).
3. Save the file.
4. Revert the file.
-> The layers list is as it was before 2.

[jazzynico (jazzynico)]

...and when moving the layer, the console shows the following message:
(inkscape.exe:1384): Gtk-CRITICAL **: gtk_tree_model_get_iter: assertion `path->depth > 0' failed

[jazzynico (jazzynico)]

Also note that the bug only shows when moving the layer at the bottom of the layers list.

[jazzynico (jazzynico)]

The console message is emitted by the LayersPanel::_handleDragDrop method (src/ui/dialog/layers.cpp), line 688, when dragging to the end and dropping into the top level (_store->iter_is_valid(_store->get_iter(up_path))).