I looked into this a bit more and also compared the latest installer to an older one. Interestingly, both were version 9.2.2 but something certainly has changed. The older installer was smaller, and although both were digitally signed there was no timestamp:
The older one offered to install Tuneup Utilities 2013, which was selected by default but which you could decline:
The newer one in addition also has OpenCandy integrated, which means it offers other third-party software for installation. The offers can be different for each person, so here's what I got:
As you can see, the behaviour seems to be similar to the toolbar you installed. I had to switch to Custom installation from Express which was selected by default, and even then I had to uncheck all 3 options.
Are OpenCandy or the programs it offers malware? That's a controversial topic so I leave that to you to decide. Looks like the offers can be skipped though by "[running] the OpenCandy powered installer from the command-line with /NOCANDY".
Malware or not, they know that people are used to blindly clicking "Next" or "OK" on any error message or dialog box or installer wizard they see, which is why I personally believe they are unethical in checking the boxes for installation of extra crapware by default.
In your case I'd suggest uninstalling the toolbar and undoing its changes (such as to your browser homepages etc.) if the uninstaller fails to revert them. Let this also be a lesson to you to read every dialog box carefully in future! They're shown for a reason, and if you let "dialog fatigue" get the best of you this and worse is exactly what will happen, and you cannot even complain beyond a point because you consented to the installation.
P.S. Having said all that, I still find EaseUS Partition Master itself to be very good and use it myself along with alternatives such as GParted.
