Why drag and drop stopped working

[fartang]

@Doitsu: Exactly the same problem here, D&D works fine with other programs, used to work fine with Calibre until a month or two ago, and now does not work with Calibre. Can you tell what firewall you are referring to and how can I disable it? Thanks

[BetterRed]

Originally Posted by fartang

@Doitsu: Exactly the same problem here, D&D works fine with other programs, used to work fine with Calibre until a month or two ago, and now does not work with Calibre. Can you tell what firewall you are referring to and how can I disable it? Thanks

@fartang

You shouldn't have to disable a firewall, but you might need to configure it to 'trust' Calibre. Calibre accesses the net quite a lot, e.g. it chats to this site to see if there are any plug-in updates.

What firewall do you use on each of your two computers - same one or different one. Do you run any other gadgets - like anti-loggers (e.g. PerfectGuard) or internet gate-keepers (e.g. App-Blocker)

I run the Zemana anti-logger, and I have to retrain it every week when I install new Calibre, it only takes a second - so doesn't bother me.

I also run the MS firewall on Win7, I used Comodo on XP. The added value Comodo gives on Win7 is marginal and for me its not worth the overhead.

BR

[Doitsu]

Originally Posted by fartang

Can you tell what firewall you are referring to and how can I disable it? Thanks

I use Commodo and simply temporarily changed the Firewall Security Level to Disabled and restarted Calibre.

Originally Posted by BetterRed

You shouldn't have to disable a firewall, but you might need to configure it to 'trust' Calibre. Calibre accesses the net quite a lot, e.g. it chats to this site to see if there are any plug-in updates.

In theory, yes, but for some reason it doesn't work. For example, Calibre can access the Internet to get metadata, but drag and drop still doesn't work.
Since I don't have drag and drop problems with other programs, I strongly suspect that there's something wrong with Calibre's Windows drag & drop code.

[DoctorOhh]

Originally Posted by Doitsu

Since I don't have drag and drop problems with other programs, I strongly suspect that there's something wrong with Calibre's Windows drag & drop code.

The converse could also be true, since every other firewall out there does not inhibit calibre's drag and drop process, I strongly suspect that there's something wrong with Commodo's code.

Kudos for providing help with this issue.

[Doitsu]

Originally Posted by dwanthny

The converse could also be true, since every other firewall out there does not inhibit calibre's drag and drop process, I strongly suspect that there's something wrong with Commodo's code.

That is definitely a strong possibility, however, IIRC, there are several different ways to implement drag & drop event handlers in Windows apps and since Comodo Firewall doesn't block drag & drop in other third party programs, it stands to reason that the drag & drop implementation in the Windows version of Calibre might not be robust enough.

Therefore the following questions remain:
1. Was there a significant change in the drag & drop event handler code and/or the shell extension code in the Windows version of Calibre in this year?
2. Does Calibre use a non-standard method to implement drag & drop that might fail under certain circumstances?

[kovidgoyal]

The drag and drop event is never reaching calibre code. And event handling in calibre is done by Qt toolkit, I highly doubt the Qt toolkit uses a non robust D7D implementation, since it is the basis of a large number of windows programs.