Known gap: a dialog a tool opens later is created DPI-aware

[skfd]

A known hole in the change, written down before it is discovered by somebody else. Not a blocker for reading the branch, but it has to be characterised before this goes upstream.

What is covered, and what is not

WinForms fixes a window's DPI awareness when the control is constructed, and DisplayPluginControl constructs the tool's control and its PluginForm inside an unaware scope. So:

• the tool's own window, and everything it builds while it is being opened — unaware, as today ✔
• anything the tool constructs later, from its own code — a settings dialog, a picker, a second form — is constructed on a thread that is aware again, so it comes out per-monitor-v2 ✘

A MessageBox is fine either way (Windows owns it). The case that matters is a tool that opens a Form of its own, laid out in 96-dpi pixels, which will be handed 144 dpi and may come out clipped or half-size.

How to see it

At 150%, with the branch build:

1. Open the sample tool and press Open Toast Notification and Do something wrong — both are host-owned and should be fine.

2. Open a real tool that has a dialog of its own. Good candidates from the tools list: anything with a Settings button, a table picker, or an export wizard.

3. For each dialog:

   • Is it sharp (aware) or blurry (unaware)?
   • Is it laid out correctly, or clipped/overlapping?
   • Screenshot either way

4. Ask the machine while the dialog is open:

   C:\Users\kk\Code\xrm-icons\tools\dpi-spike\bin\WindowProbe.exe XrmToolBox

   A dialog listed as PER_MONITOR_V2 while its tool is UNAWARE is this issue.

What the answer decides

• If tool dialogs are rare and mostly look fine, this is a documented limitation and the PR says so.
• If common tools open dialogs that break, the scheme needs the inverse: leave the UI thread unaware by default and make XrmToolBox wrap the construction of its own windows in an aware scope. That is a bigger change to the host and a much safer default for tools, and it is better to know before the PR is opened than after.

I cannot judge which it is without seeing real tools at 150%.