Crash when attempting to create a chunk with just an empty token

[kayaulai]

1. Create a token.
2. Clear the currently displayed column of the token so that it's an empty string
3. Attempt to create a chunk with only this token.

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ERROR in
action number 1
of Draw Event
for object obj_control:

ds_map_find_value argument 1 incorrect type (undefined) expecting a ds_map
at gml_Script_scr_createChunk
############################################################################################
gml_Script_scr_createChunk (line -1)
gml_Script_scr_mouseRect
gml_Object_obj_control_Draw_0