Version:           2.0 (using KDE 3.5.0 Level "a" , SUSE 10.0 UNSUPPORTED)
Compiler:          Target: i586-suse-linux
OS:                Linux (i686) release 2.6.13-15-smp

Steps to reproduce:

1. Select Hex mode in KCalc.
2. Enter 1A5CF (or any other hex number).
3. Select binary mode.
4. Copy using Ctrl+C and paste into some text box control.
5. ACTUAL RESULT: 107983 (pasted); EXPECTED: 11010010111001111 (manually typed)
6. Select octal mode.
7. copy & paste
8. ACTUAL RESULT: 107983 (pasted); EXPECTED: 322717 (typed)
9. Select *hex* mode (!)
10. copy & paste
11. ACTUAL RESULT: 0x107983 (pasted); EXPECTED: 1A5CF (typed)

Of course there is no error in decimal mode.

Two aspects to this bug:

1. that binary and octal mode copy operations copy the decimal value of the number entered (in any mode)

2. that a hex mode copy operation copies the decimal value *prefixing 0x to it* which creates the wrong impression that 107983 is a hex number (with decimal value 1079683)

Reproducibility:

The value can be entered in any mode. It is properly recognized as a value in that base system (see bug 65167) and internally converted to decimal (?). But when copying the above-reported error occurs. 

General expected behaviour:
A value must be copied as it is seen on the screen. Perhaps delimiters in decimal mode may be skipped (that's a different issue). But otherwise, I want to copy a number in the way it is seen. 

How I discovered:

I opened KCalc for using it to convert a number from hex to binary and it did not work as desired, which leads me to report this bug.

This is a bug, not wishlist:

I did not file this as a wishlist because I feel this is not a "it would be nice if it were like this" case but a "it must be like this but it is not" case. Moreover, the behaviour of prefixing 0x to a decimal value is indeed misleading mathematically and therefore a bug.