scara_monga: the image you are using is too large. Yeah it shouldn't matter but for some reason it does. In my mod the leader_fg image is a 1024x600px png @ 350kb filesize. It seemed like yours was too big for the game to load? So when I smushed it down to roughly the same size as mine it works (and produces similar results, the left side of the image is obscured/clipped by the text box). So compress, smush, and flip your image horizontally.
I am having a hell of a time getting custom tech tree branches to work. When I create them, I nest them correctly under TechTree:
however they never show up. I figured well alright, I can just go off an existing branch, say Colonization... but doing that causes the game to crash since 97.7. What's worse is that I eventually figured out that in .97.7 having said custom techs at anything other than <ResearchCost>0</ResearchCost> causes the game to crash upon entering the tech tree screen, it doesn't matter what node they are attached to.
So right now I have my custom techs "active" from the start of the game, without having to research anything, because I can't actually see any of them to begin with. I actually had them nested under the Colonization branch just fine in .95, but something changed and they didn't/don't work that way any more.
I've been working on a TechTree with no such problems. I change one tech (or two) at a time, modifying the tech, any improvements, starbase modules, or projects as needed along with all corresponding text.
I'm not sure what exactly you are trying to accomplish with your tech tree mod; for me, I'm not just changing the flavor, nor the order of the techs, but several of the techs are being completely reworked to provide different improvements altogether (which I have had to create).
Problems I've run in to:
1) changing the generic name without changing the subsequent tech's prerequ. For example, when I change a tech in order to provide a different improvement, I add the race name to the beginning of the tech's generic name. If this isn't done to the prerequ of the next tech in the tree, the rest of that branch will not display.
2) changing the internal names and tech specializations without adding the techspecializationdefs file causes problems, I think.
The process I've used (successful, so far):
1) copy a tech tree and rename all the internal names, but nothing else.
2) change the tech tree name and link to it in the factiondefs file.
3) test it out.
4) make a small change (for example, change the generic name of the colonization tech branch and then the prerequ of the industrialization and planetary improvement techs).
5) test it out.
6) repeat 4 and 5.
I'd offer more details, but I'm not sure exactly what issue you are running into... What are you trying to change?
One last suggestion, and I know this may be a pain in the butt, but have you tried starting over with a newly copied tech tree (i.e., save a base tech tree as a new file then work through your mod, transferring one tech over at a time into the new file)?
Hope this helps some! I'm super excited to see everything people are making, and I look forward to finishing my mod to share with you all!