My co-developer hates me from using other open source code modified

[~*McoreD*~]

Hi guys, I thought of posting here for more opinions because my co-developer and I have different opinions when it gets to using others open source code.

We are developers of an open source (GPL) screenshot capturing program called ZS and at the moment we are developing its successor called SX.
I wanted to add “annotate after capturing image” support with SX. With ZS in the past I also did this by slightly modifying an image editor called GSE which was part of another screenshot capturing program called GS. I thought that was best suited for my needs because out of all the other image editors out there, it was the easiest to use for quick obfuscation of sensitive areas of the screenshot and I could highlight the way I liked it too. Loading the image editor was much quicker than MS Paint or Paint.net so I successfully integrated GSE to ZS. I did not change any program titles or anything; I used them as it is and also acknowledged them in the About Window. My primary goal was to get useability perfect.

Jaex, my co-developer did not like what I did with GSE and ZS but his influence was minimal at the time with ZS because he joined later to the ZS project. Since then has significantly contributed to the projects, also made another screenshot program from scratch called ZU and now has a much larger influence. He would hate it if I do that again for SX.

He would suggest me to use Paint to annotate.

He would tell me:
highlight : http://i.imgur.com/yOGxV.png
black background: obfuscate

I told him, I don’t like to use a black background to obfuscate and the effect I want to have is http://i.imgur.com/yKnD6.png
I told him, I am a developer so I would not any time compromise myself to be forced to use something that does not fully suit my needs. For average user who depends on what’s available there is no choice. But I am not that average user; if I have the choice to mod something to work something out to suit my needs why would be stuck with less optimal solutions?

In a summary these are his opinions:

He doesn’t want to use GSE with SX because he believes it is theft. It is extremely unprofessional too he says. If I wanted annotating so much, I should be making my own. He says GSE never used other people’s libraries and wrote everything themselves. He asks me why would we advertise their app name in our app. He suggests me to take screenshots that does not require obfuscating by taking different potions of the screen.
He distinguishes this from using libraries such as SSHNET.dll because they are coded purely for reuse. He finds no problems with that – I understand totally.

So basically what he cannot stand is modifying other open source code that was not meant purely for reuse because he thinks it is unprofessional.

My arguments are, we are not doing anything commercial, our application is open source too and I provide acknowledgement; I have no competition in mind. I am mainly focused on usability and I would just reuse anything that makes my life easier to have the best outcome.

Looks like I have to have a SXmod so that I can use GSE as the image annotator because why on earth I have to compromise how I do thinks when I have the capability mod something up to suit my needs?

What do you guys think?