Since Calibre 4.0 there seems to be a bug in the BOL_NL plugin. I've posted a bug report at
https://bugs.launchpad.net/calibre/+bug/1846943 but got the answer back that the texts in the popup screens was not found in the calibre source code and the problem probably was in a plugin.
Here's the text of my bug report:
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When using Ctl-D and Alt-m to download metadata for a selected book, sometimes a popup occurs with the title 'No exact match'. In the previous calibre release I could pick a suggestion from the presented list. Since I've upgraded to calibre 4.0 this dialog does not seem to react on mouse-clicks or keyboard strokes. I can only use the window-close button, which results in a '... not responding' popup where I can select 'Force quit'. Finally I get a 'Failed to download metadata' popup which I can click away.
I've included screenshots of the popups mentioned.
I'm using calibre 4.0 on Linux Mint Mate 18.3
My active kernel is 4.15.0-65
Kind regards, Jos Kaats
PS I am more than willing to do any tracing if that's necessary.
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Kovid's reply:
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As far as I know there is no such dialog in calibre itself.
The string "No exact match" is not present in the source code and "Geen
exacte match" is not present in the translations.
Are you
using some third party plugin? Try running calibre with
calibre --ignore-plugins
and see what happens.
status invalid
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So I've enabled/disabled the metadata sources one by one and the problem appeared at BOL_NL. The customization screen of this plugin directed me to this forum, so my question is: Are the plugin developers present on this forum?