Incorrect positioning and distortion of structures when Copy-Pasting in Flex Mode

[Zhirnoff]

Description:
When copying and pasting structures in Flex Mode, the pasted structures are always inserted at a fixed offset relative to the initial copied structure. As a result, after multiple pastes, the newly inserted structures begin to distort and overlap, making the layout incorrect and difficult to work with.

This issue appears to be a side effect of the fix implemented in GitHub Issue #6132, which affected how pasted structures are positioned.

Steps to Reproduce

1. Switch to Flex Mode in Macromolecules.
2. Draw or load a structure onto the canvas.
3. Copy (Ctrl+C) and Paste (Ctrl+V) the structure multiple times.
4. Observe the position of each new pasted structure.
5. Continue pasting multiple times and observe the distortion and misalignment.

Actual behavior
The first pasted structure is inserted at a fixed offset relative to the original.
Each subsequent paste follows this same fixed offset, rather than adjusting to available space.
After multiple pastes, structures start to distort and overlap, leading to an incorrect representation.

Expected behavior
Each pasted structure should be placed in an available space without distortion. Maybe under cursor. (TBD Need to decide how it should works because algorithm of copy/paste not introduced for Macro mode)

Video

2025-02-04_16h54_31.mp4

Desktop:

• OS: Windows 11
• Browser Chrome
• Version 131.0.6778.205 (Official Build) (64-bit)

Ketcher version
[Version 3.0.0-rc.8]
Indigo version
[Version 1.28.0-rc.3]