Error message from logcat
**ERROR**: SceneShaderGLES3: Fragment Program Compilation Failed:
50:471: S0032: no default precision defined for parameter 'probe'
At: drivers/gles3/shader_gles3.cpp:167:_display_error_with_code() - SceneShaderGLES3: Fragment Program Compilation Failed:
That happened when an instanced scene was being duplicated while it also contained nodes added to it in the scene holding the instance.
Plus:
- Add comments about the logic behind all this.
- Move the null guard to where it can protect the most, but consider it a runtime error rather that a situation we expect.
Fixes#13282.
Remove an incorrect check likely left over from copying from the
normal fixed_fps update case.
Also makes sure that the preprocessing_time is always fully simulated,
rather overshooting the mark than stopping early.
- Now it is usable from both `CanvasItem` and `Spatial` editors.
- `EditorPlugin` API changes:
- `forward_draw_over_canvas()` becomes `forward_draw_over_viewport()`.
- `update_canvas()` becomes `update_overlays()`, which now triggers the update of every overlay on top of any 2D or 3D viewports present. Also now it returns the number of such viewports, which is useful whenever you need to know the number of draw-over calls you'll get.
- New: `[set/is]_force_draw_over_forwarding_enabled()` to force overlaying regardless it handles the current object type, in a similar fashion as `[set/is]_input_event_forwarding_always_enabled`. This kind of overlay is also on top of those for regular handled node types.
- New: `forward_force_draw_over_canvas()`, which is the callback that gets called for plugins that enable forced overlaying.
a) Added Backspace key support for Tree-based file dialog.
b) Fixed issue inability to select a folder in project manager (always previous folder was selected instead).
c) Open Directory mode: changed "Open" to "Select Current Folder"
d) Block "Open" button when inappropriate content is selected (for example, file when in open folder mode, or folder when in open files mode)
