Build a SplitContainer repaint sample and exploratory test matrix

[KlausLoeffelmann]

Objective

Create a sample application and exploratory test matrix for continuous SplitContainer repainting with panel payloads of increasing complexity.

Sample configurations

Provide easy switching between:

1. Light payload: simple controls and text in both panels.
2. Medium payload: mixed controls, scrolling, anchoring/docking, images, and dynamic layout.
3. Heavy payload: realistic content with at least three nested levels of TableLayoutPanel, multiple child controls, mixed docking/anchoring, and enough content to expose repaint, layout, flicker, and responsiveness problems.

Exercise horizontal and vertical SplitContainer orientations and repeated mouse and keyboard movement.

Exploratory environments

• Classic mode.
• VisualStylesMode.Net11 and the latest available mode.
• Light mode and Dark Mode.
• Local interactive session.
• Terminal Services / Remote Desktop session.
• Windows on x64.
• A non-Apple Windows on ARM device.
• A genuinely slow machine such as a Surface Go 2.

Klaus owns both a suitable non-Apple ARM machine and a Surface Go 2 and can always be asked to perform or assist with this testing.

Observations to record

• Continuous correctness of both panel contents during movement.
• Final layout correctness.
• Flicker, tearing, stale regions, blank regions, or delayed paints.
• Input responsiveness and splitter tracking.
• CPU usage, layout/paint frequency, and obvious handle or memory growth.
• Differences by visual mode, theme, orientation, hardware, and local versus remote session.

Completion criteria

• All three payload magnitudes are available and documented.
• The heavy case includes at least three nested TableLayoutPanel levels.
• Both orientations and mouse/keyboard paths are exercised.
• Classic, light, Dark Mode, and Terminal Services / Remote Desktop results are recorded.
• x64, Windows on ARM, and Surface Go 2 or equivalently slow hardware results are recorded.
• Reproduction and exploratory-testing instructions are clear enough for another tester to follow.