The issue you are experiencing could be caused by a minor corruption of the preferences. It is recommended that you save your preferences and attempt a reset to see if this resolves your issue.
Removing your preferences, which also clears Altium cache and some registry entries, will leave your Altium software in a freshly installed state, so if you connect to a private license or managed content server, please record that information before starting this process.
If you'd like to follow along with screen shots, see the choice for "Remove Preferences" while following the steps in this documentation:
1. Back up the Altium Designer preferences:
-Open the Preferences Panel.
-Press the Save... button, at the bottom left of the dialog box.
-Choose a location & file name for the backup file, and save it.
(If required, these can be restored later by using the Load... button, found in the same dialog.)
*** If you connect to a private license or managed content server, please record that information before continuing. (This information can be found by clicking on the Setup private license server control near the bottom of the License Management page) ***
*** If you are using the NEXUS client, record your server information so you can log in again when you re-start. ***
-Close Altium Designer
2. Remove the Preferences:
- Start Menu ► Control Panel ► Programs and Features
-Select the version of Altium Designer from which you wish to remove the preferences in the list box
-Select ‘Uninstall’ to start the Altium Uninstaller dialog
-Select 'Remove Preferences' from the Uninstaller dialog <ok>, <finish>.
-Close the un-installer
3. Run Altium Designer and be sure not to import your preferences if prompted at startup. Altium will be in a state of starting up for the first time, so you will need to perform your licensing steps again. If this does not resolve your issue, you can re-load your preferences later from the file you saved in the first step.
If it does resolve your issue, you can manually set your preferences over again. If this sounds onerous, you could experiment with reloading individual sections of your preferences:
From the Preferences panel, click the Load… button, at the bottom of the dialog box, choose the file, expand "Show options page list" if necessary, to access and select /de-select the sections desired and then click OK.