Qiqqa does not immediately update all UI interfaces as you work

[GerHobbelt]

Container issue for the problem underlying #161 and other observations:

• add a PDF via browser, sniffer or otherwise and don't see it automatically updated in the Library list view

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Looks to me like the refresh/update process in Qiqqa is a tad b0rked.

[GerHobbelt]

From the TODO List Project Notes by way of #247, copied here:

Qiqqa sure needs an MVVM/MV* overhaul which takes the distribution of work serious in the software architecture as this is becoming a mess. (Intent: Document/library work in background worker threads, UI thread only does UI I/O + minimal UI-specific work.)

[GerHobbelt]

Note to self: looks like part of the problem is that the background work done in some tasks, which is then finished by a UI update, are severely delayed as they are added to a sometimes already huge SafeThreadPool work queue (my libraries have lots of pending OCR/TextExtract), thus: required work is wiating in the threadpool queue and only gets done once a lot of the other stuff has been completed. Only then, of course, does the UI update happen.

Hence it might be good to look at a prioritized queue where UI-updating tasks get priority over pure background library update work, like OCR/TextExtract of documents which are currently not displayed on screen.

To be investigated further....