When using the renderers in PACS interaction mode using keyboard modifiers (e.g. control + button to zoom), the renderer may become unresponsive when the modifier key is released too early.

To reproduce:

• Load an image file;
• Press and hold the control key;
• Press and drag the right mouse button over a renderer window (do not release yet);
• Release the control key;
• Release the right mouse button.

The renderers now do not initiate any mouse interaction when clicking/dragging.

To 'unfreeze':

• Press and hold the control key;
• Press and hold the right mouse button over a renderer window;
• Release the right mouse button;
• Release the control key.

All interactivity is now as it should be.

Reproduced on Windows (release 2021 and 2018) and macOS.