Windows 10 Home 64, with NVIDIA GeForce 940MX
Broken: 2.8 c21ceb3 (win64-vc14) and 5dab34d (win64-vc14)
Like it says in the title when a NodeGroup has an unconnected socket, the textbox/slider/color selector for that socket won't work in Eevee renderer.
**Exact steps for others to reproduce the error**
In a new file (default cube):
- Assign a new material to the default cube.
- Set shading to "Material".
- Switch to Node Editor (this is easier to notice if the window is split to keep a 3D View open.)
- Select Principled BSDF in Node Editor, and group it (Ctrl-G). This is simply an example, but from my experience, this happens with every NodeGroup.
- The values assigned in the textboxes, sliders and color boxes of the NodeGroup won't have any effect on the rendering anymore.
- If a Value Node or RGB Node is connected to them, and then used to change the parameter, everything works fine, but as soon as they're disconnected, it stops working again.
- This happens in Eevee renderer, but a very similar issue happens in Cycles, where the renderer won't update material parameters until the user switches to another renderer, and back to Cycles. In this case, the NodeGroup inputs work, but only after switching renderer.