Client GUI not showing up (Ubuntu 17.10)

Hey,

i recenetly got a new Laptop and wanted to install seafile. At first I installed seafile through the GNOME software center. This was version 6.0.7. Everything was working perfect except the whole GUI was scaled up too much, I can’t see the bottom of the client. So I tried to install version 6.1.0 as mentioned in the manual (I had to install a special version of the libevent library for this).
But now the sync was gone and couldn’t manage to get it back (and the scaling problem was still there). So I wanted to go back to version 6.0.7. I removed seafile again, the repository as well and installed version 6.0.7.

But now the GUI does not show up. I get the window where I get asked where to put the default libraries but nothing more. Even no indicator icon. When launching again it shows me that seafile is already running and asks for killing it.
I also tried to remove the ~/.ccnet and ~/Seafile/.seafile-data folders but nothing changed.

This is the content of the log files:

ccnet.log

[09/02/17 18:11:08] ccnet-daemon.c(193): starting ccnet client 6.0.4
[09/02/17 18:11:08] ../common/session.c(132): using config file /home/jack/.ccnet/ccnet.conf
[09/02/17 18:11:08] ../common/session.c(455): socket file exists, delete it anyway
[09/02/17 18:11:08] ../common/session.c(484): Listen on /home/jack/.ccnet/ccnet.sock for local clients
[09/02/17 18:11:08] ../common/session.c(290): Update pubinfo file
[09/02/17 18:11:09] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:09] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:09] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:09] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:10] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:10] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:10] ../common/peer.c(943): Local peer down
[09/02/17 18:11:10] ../common/peer.c(943): Local peer down
[09/02/17 18:11:10] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:10] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:10] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:11] ../common/session.c(398): Accepted a local client
[09/02/17 18:11:11] ../common/session.c(398): Accepted a local client
[09/02/17 18:12:17] ../common/session.c(398): Accepted a local client
[09/02/17 18:12:22] ../common/peer.c(943): Local peer down
[09/02/17 18:12:51] ../common/session.c(398): Accepted a local client
[09/02/17 18:12:56] ../common/peer.c(943): Local peer down

applet.log

[02.09.2017 18:11:08]starting ccnet:  ("-c", "/home/jack/.ccnet")
[02.09.2017 18:11:09]trying to connect to ccnet daemon...

[02.09.2017 18:11:09]connected to ccnet daemon

[02.09.2017 18:11:09]starting seaf-daemon:  ("-c", "/home/jack/.ccnet", "-d", "/home/jack/Seafile/.seafile-data", "-w", "/home/jack/Seafile")
[02.09.2017 18:11:10][Rpc Client] connected to daemon
[02.09.2017 18:11:10][Rpc Client] connected to daemon
[02.09.2017 18:11:10][MessageListener] connected to daemon
[02.09.2017 18:11:10]Unable to get config value download_limit: Config not exists
[02.09.2017 18:11:10]Unable to get config value upload_limit: Config not exists
[02.09.2017 18:11:10]Starting the network status detector
[02.09.2017 18:11:11][Rpc Client] connected to daemon

and seafile.log

[09/02/17 18:11:09] seaf-daemon.c(558): starting seafile client 6.0.7
[09/02/17 18:11:09] ../common/mq-mgr.c(60): [mq client] mq cilent is started
[09/02/17 18:11:09] ../common/mq-mgr.c(106): [mq mgr] publish to heartbeat mq: seafile.heartbeat

Do you have any ideas?

When I try to debug nothing shows up. I first deleted the both folders again and then run

[18:47] jack@laptop ~ >export SEAFILE_DEBUG=all
[18:47] jack@laptop ~ >seafile-applet 
done
Successly create ccnet config dir /home/jack/.ccnet.
** (seafile-applet:3373): WARNING **: Get log file /home/jack/.ccnet/logs/applet.log stat failed errno=2.
** (seafile-applet:3373): WARNING **: Get log file /home/jack/.ccnet/logs/seafile.log stat failed errno=2.

I could again select the default storage folder but then I waited 10 minutes and nothing happend

For the scaling problem, you could try:
http://doc.qt.io/qt-5/highdpi.html#high-dpi-support-in-qt