Hi,

i have tagged a bunch of new photos and detected that my rsync backup script didn't transfer the newly tagged files. I checked my settings and testet withe a new import in a test album.
Result:
The Option "Use lazy synchronization" causes that no tags will be written to the files neither with the button "Write Tags to file" or at closing the digikam app.

i then repeated with the option unchecked and then the tags will be synced like in the older versions of digikam.

With "lazy":
[philipp@blue 2016-08-31-Testalbum]$ exiftool *3123* | grep Portrait
[philipp@blue 2016-08-31-Testalbum]$

Without "lazy":
exiftool *3123* | grep Portrait
Categories                      : <Categories><Category Assigned="0">Fotografie<Category Assigned="1">Portrait</Category><Category Assigned="1">Tiefenschärfe</Category></Category></Categories>
Tags List                       : Fotografie/Tiefenschärfe, Fotografie/Portrait
Subject                         : Tiefenschärfe, Portrait
Last Keyword XMP                : Fotografie/Tiefenschärfe, Fotografie/Portrait
Hierarchical Subject            : Fotografie|Tiefenschärfe, Fotografie|Portrait
Catalog Sets                    : Fotografie|Tiefenschärfe, Fotografie|Portrait
Keywords                        : Tiefenschärfe, Portrait

I've attached a screenshot, in which you can see (even after closing an reopening digikam) that the tags are also not displayed in the "edit metadata" dialog.


Reproducible: Always

Steps to Reproduce:
1. Set the "Use lazy synchronisation" option in digikam
2. Import Photos in digikam
3. Tag the pictures
4. check with exiftool if the tags are correctly written to the files

Actual Results:  
The tags are not written into the files
[philipp@blue 2016-08-31-Testalbum]$ exiftool *3123* | grep Portrait
[philipp@blue 2016-08-31-Testalbum]$

Expected Results:  
The tags should be written into the files
(Here without "lazy synchronisation")
exiftool *3123* | grep Portrait
Categories                      : <Categories><Category Assigned="0">Fotografie<Category Assigned="1">Portrait</Category><Category Assigned="1">Tiefenschärfe</Category></Category></Categories>
Tags List                       : Fotografie/Tiefenschärfe, Fotografie/Portrait
Subject                         : Tiefenschärfe, Portrait
Last Keyword XMP                : Fotografie/Tiefenschärfe, Fotografie/Portrait
Hierarchical Subject            : Fotografie|Tiefenschärfe, Fotografie|Portrait
Catalog Sets                    : Fotografie|Tiefenschärfe, Fotografie|Portrait
Keywords                        : Tiefenschärfe, Portrait