Primary category to blogger

Hi there,

if a blogger starts a new post (and his blog category is not the primary) he has to choose the right category on the right side...

For example: User stackideas is logged on but the primary category is M+M Australia 2016.
Now, if he creates a new post, this one will be created under M+M and not in his own blog...

Is it possible to automaticly change the active category to his last used category?

kind regards
Heiner