Referecence to previous objects in titles are not visible when signal selected (under linux, at least)

[StefanoPierini-Codra]

Describe the bug
When an object (signal/image) is selected, the link to previous signal in his title has the same color that the selection has. It is thus impossible to read.

To Reproduce
Steps to reproduce the behavior:

1. Create a signal
2. Create a signal from it (i.e. with an operation)
3. Select it
4. Look

Screenshots

Additional context
Seen under datalab in WSL, while developing #149.

[StefanoPierini-Codra]

This bug required a small fix, originally implemented in the same branch as #149. As the integration of that branch has been delayed, I suggest to cherry pick c3ea3de in order to fix it faster.