After a weekend of hard and seamless work, it seems that my PCB has now grown in size such that it does not want to save.
EasyEDA has no problems saving Schematics and smaller PCB's but the large one does not work any more.
This is what it looks like now at size 290x166mm:
![image.png](//image.easyeda.com/pullimage/6bcMS5cxXdJreAAhVN2XhNcW5l5G2KVG68q9rWwY.png)
Chrome
65.0.3325.181
Linux
EasyEDA
5.4.9