Created attachment 147902 [details]
zip file with documents to show the bug

In special cases Calc freezes, when cell content should be cut or copied.

Reproducing the problem:
- open "altix_Nummern_Test_Einfrieren_V4d2.ods" or "altix_Nummern_Test_Einfrieren_V4d2.ods" from attached zip file
- copy (e.g.) row 14 and paste it into (e.g.) row 11 
- select a text in any cell and try to copy or cut it
Result: Calc freezes (doesn't respond)

The freeze occurs also when other rows are copied and pasted (therefor the "(e.g.)". Ooccasionally Calc doesn't freeze  at copy or cut, but I couldn't reproduce these cases until now.

As I have seen formulas reffering other cells are causing the freeze. When the same procedure is done with "altix_Nummern_Test_Einfrieren_V4l_no_freeze.ods" from attached zip file Calc doesn't freeze.

Tested with Version: 6.2.0.1 (x64)
Build-ID: 0412ee99e862f384c1106d0841a950c4cfaa9df1
CPU-Threads: 4; BS: Windows 10.0; UI-Render: Standard; VCL: win; 
Gebietsschema: de-DE (de_DE); UI-Sprache: de-DE
Calc: threaded
and with 
Version: 6.3.0.0.alpha0+ (x64)
Build ID: 2c5c20b19c349a4b7f6d78d69d8d57f9af5c351c
CPU threads: 4; OS: Windows 10.0; UI render: GL; VCL: win; 
TinderBox: Win-x86_64@42, Branch:master, Time: 2018-12-23_00:18:09
Locale: de-DE (de_DE); UI-Language: en-US
Calc: threaded
and not reproduced with
Version: 6.1.4.2 (x64)
Build-ID: 9d0f32d1f0b509096fd65e0d4bec26ddd1938fd3
CPU-Threads: 4; BS: Windows 10.0; UI-Render: GL; 
Gebietsschema: de-DE (de_DE); Calc: CL