Track properties on multiple tracks works only on first

[Viktor-Urban]

1. Select multiple tracks that do not have any album/artist information in their tags.
2. RMB for popup, select Track Properties
3. Fill artist and album data, LMB on Apply, confirm applying to all tracks

Expected Behavior

All tracks should be updated correctly.

Current Behavior

First of the selected tracks is updated correctly.
All other tracks only receive first letter of both album and artist values.
Interestingly, this process can be repeated. Select all tracks except the first one, now the editing window contains the first character of both previously entered values. If I now fill the values and click Apply again, the first selected track (second in total) again is updated correctly and all remaining tracks receive one more letter, so now they have 2 letters from Artist and Album...
Note: I also tried date and genre fields, same behaviour. Didn't try any others.

Environment

Linux 4.16.13-pclos1 SMP Wed May 30 20:54:58 CDT 2018 x86_64 x86_64 x86_64 GNU/Linux
package: exaile-4.0.2-1pclos2020
Exaile's About:
GStreamer: 1.18.3
GTK+: 3.24.24
GTK+ theme: Breeze
Locale: en_US UTF-8
Mutagen: 1.42.0
PyGObject: 3.28.2
Python: 2.7.9

[luzip665]

Can be reproduced without clicking on apply.

Steps:
I got three track with same artist.
So, the all button is active

If I press the first key in the artist field, it happens:

• The char is set to all artists fields
• The all button is being deactivated

If I press the second key nothing happens to the other tracks.