[Bug]: When in sketch pad, entering type mode removes sketch pad

[massytech]

Description

When in sketch pad, entering type mode ('t') causes sketch pad background to disappear.

Current Behavior

After entering sketch pad with CTRL+W or CTRL+K, draw components work fine. The moment you enter typing mode, the sketch pad background disappears and screen contents are visible again (draw content is retained)

Expected Behavior

Sketch pad background should persist (similar to draw tools)

Steps to Reproduce

1. Enter drawing mode (Ctrl + 2)
2. Enter sketch pad (Ctrl + W or Ctrl + K)
3. Draw a line by holding down the Shift key
4. Draw a rectangle with the Ctrl key
5. Press 't' to enter type mode

Product Version

ZoomIt 12.21.0

macOS Version

macOS Tahoe 26.6

Additional Context

No response

[EhsanAzish80]

I reproduced the state transition in the code. Entering typing mode calls exitDrawingMode(), which unconditionally clears the active sketch-pad background. I have a fix that preserves the background specifically when transitioning into typing mode while retaining the existing clearing behavior for normal drawing exits. I also added a regression self-test; the complete self-test suite and the ZoomIt macOS build pass.