Android Studio Palette is disabled

Question

I haven't see since when, but my palette doesn't show up, I did some search about it, they say: "Restart the project", but I don't know why when I go in View >> Tool Windows, palette is disabled:

I did a update too, to see if it appeared but it didn't. Logcat say:

0 warnings.
0 errors.

Console:

Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
AGPBI: {"kind":"ERROR","text":"Resource id cannot be an empty string (at \u0027id\u0027 with value \u0027@+id/\u0027).","sourcePath":"C:\\Users\\...\\AndroidStudioProjects\\Solutis\\app\\src\\main\\res\\layout\\activity_contact.xml","position":{"startLine":7,"startColumn":17,"startOffset":308,"endColumn":22,"endOffset":313},"original":""}


 FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processDebugResources'.
> com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'C:\Users\...\AppData\Local\Android\Sdk\build-tools\22.0.1\aapt.exe'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

Solution 1

I found a lot of post with this problem, and i found why, the palette is not disabled, it's activated but it's hidden here:

So you juste have to stretch it

Solution 2

You can restore your layout to default by navigating to Window/Restore Default Layout: