I have just experienced a similar issue but was working with a custom layer for a UD table. After spending heaps of time building the application, I noticed the New icon had disappeared from Details page (but was still visible on Landing Page).
So, I went to Advanced > Tools and noticed there was no toolNew in the list. I added toolNew record and it broke everything…after going around in circles trying to add/delete from Tools on Details page, Tools on Landing Page, Tools in Dataviews I got to a point where the New icon/button did not work on either page and I could no longer click through from record on Landing Page to get to Details page. (I didn’t make any changes to Events)
I searched for your Problem record but it doesn’t seem to exist anymore? But ended up coming across the following problems / KB article:
PRB0253865 AppStudio: When deleting a tool in a new layer, the bindings for all subsequent tools are off by one.
PRB0269842 AppStudio: Application Studio does not save Tools that were added to a Custom App.
KB0138331 Tools Icons Missing after changes to Custom Layers
Ultimately the KB article solved my problem. It suggests that making multiple changes to a Custom Layer can cause the Ep Binding fields to be cleared and in turn cause Tool icon’s not to load. Once I added the EpBinding’s back, the out of the box New icons reappeared and functioned correctly. I was then able to go to Advanced > Tools and delete the toolNew record I had created.
Hopefully this info might help someone else down the line 