Crash when getting a blueprint book item from the shortcut bar

[raiguard]

Factorio 0.18.37 just came out, and with it, massive overhauls to the blueprint library. Now, when you try to get a new blueprint book item from the shortcut bar, the mod crashes.

Here is my savegame. To reproduce, simply try to get a blueprint book from the shortcut bar. It will immediately crash.

factorio-current.log

The mod Blueprint Extensions (0.5.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event BlueprintExtensions::on_player_cursor_stack_changed (ID 29)
Index out of inventory bounds.
stack traceback:
	__BlueprintExtensions__/util.lua:11: in function 'get_blueprint'
	__BlueprintExtensions__/gui.lua:58: in function 'update_visibility'
	__BlueprintExtensions__/control.lua:123: in function '?'
	__BlueprintExtensions__/control.lua:41: in function <__BlueprintExtensions__/control.lua:39>
stack traceback:
	[C]: in function '__index'
	__BlueprintExtensions__/util.lua:11: in function 'get_blueprint'
	__BlueprintExtensions__/gui.lua:58: in function 'update_visibility'
	__BlueprintExtensions__/control.lua:123: in function '?'
	__BlueprintExtensions__/control.lua:41: in function <__BlueprintExtensions__/control.lua:39>

[FritzHugo3]

#42 (comment)
Fix