Jay W. said: Huh...that's weird! From your screenshot, it looks like you're in the right place, but I'll walk through it step-by-step just to be safe. I create a character, select class (I've used bard, sorcerer, and warlock), and then select custom species. I give the species a name, speed, and size. From there, I scroll down to "features." I give the new feature a name and description, then click "+Add" under Modifiers. I select "Custom DC" at the very bottom of the "Choose Modifier" dropdown, which brings up a dropdown where you can choose Flat Value or Detailed Calculation. Flat Value works fine; when you give it a non-zero value, the "Apply" button becomes usable. Selecting Detailed Calculation brings up the choices shown in your screenshot. But--and here's where it gets interesting--when I select Add Ability Score, Add Character Level, or Add Proficiency Bonus (or any combination of them), the "Apply" button remains grayed out and unusable. When I select Add Flat Value and set it to a non-zero value, the button becomes usable just like if I had selected Flat Value from the initial dropdown. Interestingly, if I select Add Flat Value in addition to any (or all) of the other options, the "Apply" button becomes usable. The same thing happens in the custom background tab. From your screenshot, it looks like this is exactly what you're doing too, but I wanted to be as clear as possible just to be safe! I recently switched over to Firefox, so it occurred to me that the browser might be the issue. So I tried it on Chrome and got the exact same issue. I tried restarting my laptop and reloading everything, but that didn't help. I also tried it in two different games, both JumpGate. Both games have the Teleport, TokenMod, and Aura/Tint HealthColors API mods running. Now I'm *really* curious to see if you can reproduce the issue, or if anyone else has encountered it, or if it's just me! Ah, the more detail helped! This is specific to when the modifier builder is being used inside the builder before level 1, not the sheet. I've been able to identify the issue and make a ticket for it. In the meantime, I know this is annoying, but if you finish building the character, click Level Up to get back into the builder, and then build the custom DC it should work. A lot of custom DCs are something like 8 + wisdom or something similar, so if you include that flat value as part of your detailed calculation it should also work. Basically what happened here is that this form was originally built to be used sheet and it's marked as "complete and ready to save" when it has a value that evaluates to above 0. But the way we evaluate these values doesn't work until the values exist on the sheet. So, if your character hasn't been built once, its PB and ability scores and character level are all effectively 0, so adding any of those without a flat value means it evaluates to 0, which disables it. Building the character once will get those base ability scores/PB/level onto your sheet to avoid that issue, and adding a flat value means that it will always be above 0, so that also avoids that issue. JD said: ISSUE: I can't link a token bar to the hp attribute value without it automatically also linking to the hp_max value, which i do not want. This Works fine on 5e2014, but with 5e2024 even setting the hp value and then explicitly clearing the bar_max using token mod as shown below only lasts until the token is subsequently processed in any way. !token-mod {{ --set bar3_link|hp bar3_max| }} This works just fine on 5e2014 - am I missing an opt-out checkbox for the 2024 feature? Or is this ' helpful ' code that needs a think, and then a rethink? This is the first time I've seen this use case - I'll look into it and see if we can get a version of HP that doesn't also include the max. The 2024 sheet isn't built like the 2014 sheet, so I can see token mod not doing what you'd expect here.