When merging two cyclic sequences in the Sequence mode, they disappear from the canvas

[ViktoriaTkacheva]

Steps to Reproduce

1. Switch to the Macro mode

2. Draw two cyclic sequences, consisting of any 4 nucleotides, for example:

   

3. Switch to the Sequence mode – the Text-editing mode

   

4. Try to merge these two sequences

   

5. Switch to the Flex mode and move all nucleotides apart from each other so that all bonds are visible

Actual behavior
In the Sequence mode, the cyclic sequences disappear from the canvas. But in the Flex mode, a new bond between two cyclic sequences is displayed, although there are no free APs in these two sequences

Expected behavior
If the nucleotides on the ends of sequences do not have a free AP R1 or R2 at the place, where they merge, an error message appears on the canvas

Error Message:
It is impossible to merge fragments. Attachment point to establish bonds are not available.

Screenshots

2024-05-29_10h40_38.mp4

Desktop (please complete the following information):

• OS: Windows 10 Pro (version 22H2) x64
• Browser: Сhrome
• Version: (125.0.6422.113) x64

Ketcher version 2.21.0-rc.2, Build at 2024-05-28; 14:29:04

Can be related #4548, #4706

[NadezhdaPeskun]

Should be verified with next Issues: (#4708, #4575, #4506, #4706) + #4328
Error Message should appear:
Error Message:
It is impossible to merge fragments. Attachment point to establish bonds are not available.

[AlexeyGirin]

Not fixed.
Both sequences simply disappears from the canvas.

0. Switch to Macro
1. Load from file: two cycles.zip
2. Go to Sequence mode
3. Edit top sequence
4. Put cursor at the end of the line
5. Press Del button

Actual behavior:
Both sequences simply disappears from the canvas.

Expected behavior:
Error message appears: It is impossible to merge fragments. Attachment point to establish bonds are not available.

2024-06-04_12h47_43.mp4

[AlexeyGirin]

Verified.

• Indigo Toolkit Version 1.21.0-rc.1.0-g9194599b2-wasm32-wasm-clang-19.0.0
• Ketcher Version 2.22.0-rc.3 Build at 2024-06-10; 12:34:49
• Chrome Version 125.0.6422.142 (Official Build) (64-bit)
• Windows 10