Hello everyone.
I am trying to implement a simple utility that I would like to keep it at the background and never be able to come in front of windows. I tried setting the window as backdrop, but that didn't make the trick.
I believe amigaamp is doing that pretty well, where it can be set above the workbench but always below other apps.
Does anyone have any ideas?

I'm curious; what about making the window a backdrop window didn't work for you?
If I remember right, setting it as a backdrop makes it immovable, but it doesn't make it stay at the back all the time. There is a possibility that I set it wrong, so I can try that again, but I wonder if that is what needs to be used or there is a need to have something else as well.
Does "WINDOW_FrontBack" help somehow?
...
Change window depth arrangement via WindowToFront() or WindowToBack(). Accepted settings:
WT_FRONT - bring window to front.
WT_BACK - put window to back
...
AOS4.1/SAM460ex/PPC460EX-1155MHZ/2048MB/RadeonRX550/SSD240GB/DVDRW :-P
Yesteday I found that having WA_Backdrop to TRUE when the window is created is enough to have it behind all the applications and also being locked in position. But I feel there might be a bug when you set it dynamically with SetAttrs(). I still investigate if this is a bug in my code, or a system one, and for that, I might need to create a small demo code that reproduces it.
Unless if you guys have any ideas about it, or any example code. I will keep you informed.
Are you using native Intuition windows, or window.class windows?
I've always been under the impression that making a window a backdrop window is something you can only do when the window is created, not something you can change on the fly. The autodocs for SetWindowAttr() don't show WA_Backdrop as one of the attributes that may be changed.
The autodocs for window.class do say that WA_Backdrop may be changed, as long as the window is not open at the time. That's not really inconsistent, as WA_Backdrop would then be used when opening (i.e., creating) the window, meeting the apparent requirement that backdrop windows have to be created as such.
Maybe you can iconify window, set WA_Backdrop tag and uniconify window.
AOS4.1/SAM460ex/PPC460EX-1155MHZ/2048MB/RadeonRX550/SSD240GB/DVDRW :-P
The solution I found so far, is to close the window and then reopen it, so that it takes the update backdrop attribute.